Plasma processing apparatus including a plurality of plasma processing units having reduced variation

ABSTRACT

A plasma processing apparatus comprising a plurality of plasma processing units is provided. Each of the plasma processing units has a matching circuit connected between a radiofrequency generator and a plasma excitation electrode. Among these plasma processing units, a variation &lt;RA&gt; between the maximum and minimum values of input-terminal-side AC resistances RA of the matching circuits defined by &lt;RA&gt;=(RA max −RA min )/(RA max +RA min ) is adjusted to be less than 0.5. A variation between the maximum and minimum values of output-terminal-side AC resistances RB of the matching circuits defined by &lt;RB&gt;=(RB max −RB min )/(RB max +RB min ) is also adjusted to be less than 0.5. The plasma processing units can be adjusted to achieve substantially uniform plasma results in a shorter period of time.

This application is a divisional of U.S. patent application Ser. No.09/992,399, filed on Nov. 6, 2001, now U.S. Pat. No. 6,806,438 whichclaims priority to Japanese Patent Application No. 2000-341076, filed onNov. 8, 2000, both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plasma processing apparatus, a plasmaprocessing system, a performance validation system, and an inspectionmethod therefor. The present invention can be suitably applied to aplasma processing apparatus having a plurality of plasma processingunits so as to minimize the variation among the plurality of the plasmaprocessing chambers and to improve the deposition characteristics usinga power of higher frequencies.

2. Description of the Related Art

FIG. 33 illustrates a typical conventional dual-frequency excitationplasma processing unit which constitutes a plasma processing apparatusand performs a plasma process such as a chemical vapor deposition (CVD)process, a sputtering process, a dry etching process, or an ashingprocess.

In the plasma processing unit shown in FIG. 33, a matching circuit 2A isconnected between a radiofrequency generator 1 and a plasma excitationelectrode 4. The matching circuit 2A matches the impedances of theradiofrequency generator 1 and the excitation electrode 4.

Radiofrequency power generated from the radiofrequency generator 1 issupplied to the plasma excitation electrode 4 through the matchingcircuit 2A and a feed plate 3. The matching circuit 2A is accommodatedin a matching box 2 which is a housing composed of a conductivematerial. The plasma excitation electrode 4 and the feed plate 3 arecovered by a chassis 21 made of a conductor.

An annular projection 4 a is provided on the bottom face of the plasmaexcitation electrode (cathode) 4, and a shower plate 5 having many holes7 comes into contact with the projection 4 a below the plasma excitationelectrode 4. The plasma excitation electrode 4 and the shower plate 5define a space 6. A gas feeding tube 17 comprising a conductor isconnected to the space 6 and is provided with an insulator 17 a at themiddle thereof so as to insulate the plasma excitation electrode 4 andthe gas source.

Gas from the gas feeding tube 17 is introduced inside a plasmaprocessing chamber 60 composed of a chamber wall 10, via the holes 7 inthe shower plate 5. An insulator 9 is disposed between the chamber wall10 and the plasma excitation electrode (cathode) 4 to provide insulationtherebetween. The exhaust system is omitted from the drawing.

A wafer susceptor (susceptor electrode) 8 which holds a substrate 16 andalso functions as another plasma excitation electrode is installedinside the plasma processing chamber 60. A susceptor shield 12 isdisposed under the wafer susceptor 8.

The susceptor shield 12 comprises a shield supporting plate 12A forsupporting the susceptor electrode 8 and a supporting cylinder 12Bextending downward from the center of the shield supporting plate 12A.The supporting cylinder 12B extends through a chamber bottom 10A, andthe lower portion of the supporting cylinder 12B and the chamber bottom10A are hermetically sealed with bellows 11.

The shaft 13 and the susceptor electrode 8 are electrically isolatedfrom the susceptor shield 12 by a gap between the susceptor shield 12and the susceptor electrode 8 and by insulators 12C provided around theshaft 13. The insulators 12C also serve to maintain high vacuum in theplasma processing chamber 60. The susceptor electrode 8 and thesusceptor shield 12 can be moved vertically by the bellows 11 so as tocontrol the distance between plasma excitation electrodes 4 and thesusceptor electrode 8.

The susceptor electrode 8 is connected to a second radiofrequencygenerator 15 via the shaft 13 and a matching circuit accommodated in amatching box 14. The chamber wall 10 and the susceptor shield 12 havethe same DC potential.

FIG. 34 illustrates another conventional plasma processing unit. Unlikethe plasma processing unit shown in FIG. 33, the plasma processing unitshown in FIG. 34 is of a single-frequency excitation type. In otherwords, radiofrequency power is supplied only to the cathode electrode 4and the susceptor electrode 8 is grounded. Moreover, the matching box 14and the radiofrequency generator 15 shown in FIG. 33 are not provided.The susceptor electrode 8 and the chamber wall 10 have the same DCpotential.

In these plasma processing units, power with a frequency ofapproximately 13.56 MHz is generally supplied in order to generate aplasma between the electrodes 4 and 8. A plasma process such as aplasma-enhanced CVD process, a sputtering process, a dry etchingprocess, or an ashing process is then performed using the plasma.

The operation validation and performance evaluation of theabove-described plasma processing units have been conducted by actuallyperforming the process such as deposition and then evaluating thedeposition characteristics thereof according to following Procedures:

Procedure (1) Deposition Rate and Planar Uniformity

Step 1: Depositing a desired layer on a 6-inch substrate by aplasma-enhanced CVD process.

Step 2: Patterning a resist layer.

Step 3: Dry-etching the layer.

Step 4: Removing the resist layer by ashing.

Step 5: Measuring the surface roughness using a contact displacementmeter to determine the layer thickness.

Step 6: Calculating the deposition rate from the deposition time and thelayer thickness.

Step 7: Measuring the planar uniformity at 16 points on the substratesurface.

Procedure (2) BHF ERching rate

A resist mask is patterned as in Steps 1 and 2 in (1) above.

Step 3: Immersing the substrate in a buffered hydrofluoric acid (BHF)solution for one minute to etch the layer.

Step 4: Rinsing the substrate with deionized water, drying thesubstrate, and separating the resist mask using a mixture of sulfuricacid and hydrogen peroxide (H₂SO₄+H₂O₂)

Step 5: Measuring the surface roughness as in Step 5 in Procedure (1) todetermine the layer thickness after the etching.

Step 6: Calculating the etching rate from the immersion time and thereduced layer thickness.

Procedure (3) Isolation Voltage

Step 1: Depositing a conductive layer on a glass substrate by asputtering method and patterning the conductive layer to form a lowerelectrode.

Step 2: Depositing an insulating layer by a plasma-enhanced CVD method.

Step 3: Forming an upper electrode as in Step 1.

Step 4: Forming a contact hole for the lower electrode.

Step 5: Measuring the current-voltage characteristics (I–Vcharacteristics) of the upper and lower electrodes by using probes whileapplying a voltage up to approximately 200 V.

Step 6: Defining the isolation voltage as the voltage V at 100 pAcorresponding 1 μA/cm² in a 100 μm square electrode.

The plasma processing apparatus has been required to achieve a higherplasma processing rate (the deposition rate or the processing speed),increased productivity, and improved planar uniformity of the plasmaprocessing (uniformity in the distribution of the layer thickness in aplanar direction and uniformity in the distribution of the processvariation in the planar direction). As the size of substrates has beenincreasing in recent years, the requirement of planar uniformity hasbecome tighter. Moreover, as the size of the substrate is increased, thepower required is also increased to the order of kilowatts, thusincreasing the power consumption. Accordingly, as the capacity of thepower supply increases, both the cost for developing the power supplyand the power consumption during the operation of the apparatus areincreased. In this respect, it is desirable to reduce the operationcosts.

Furthermore, an increase in power consumption leads to an increase inemission of carbon dioxide which places a burden on the environment.Since the power consumption is increased by the combination of increasein the size of substrates and a low power consumption efficiency,reduction of the carbon dioxide emission is desired.

The density of the plasma generated can be improved by increasing theplasma excitation frequency. For example, a frequency in the VHF band of30 MHz or more can be used instead of the conventional 13.56 MHz. Thus,one possible way to improve the deposition rate of a depositionapparatus such as a plasma-enhanced CVD apparatus is to employ a higherplasma excitation frequency.

In a plasma processing apparatus having a plurality of theabove-described plasma processing units, variation in plasma processingamong the plasma processing units and their matching circuits isrequired to be reduced, so that the plasma processing rate (depositionrate when applied to a deposition process), productivity, and uniformityin the plasma process in the planar direction of a workpiece (planardistribution in the layer thickness) can be made substantially the sameamong the workpieces plasma-treated in different plasma processingunits.

The plasma processing apparatus is also required to yield substantiallythe same process results by applying the same process recipe specifyingexternal parameters for respective plasma processing units such as gasflow, gas pressure, power supply, and process time.

It is desired to both reduce the time required for adjusting the plasmaprocessing apparatus newly installed or subjected to maintenance toachieve substantially the same process results by applying the samerecipe and eliminate the variation among the plurality of plasmaprocessing units, as well as the cost required for such adjustment.

Furthermore, reduction in the variation among the plasma processingunits has also been required for a plasma processing system comprising aplurality of such plasma processing apparatuses.

The above-described plasma processing unit is designed to use power witha frequency of approximately 13.56 MHz and is not suited for power ofhigher frequencies. Specifically, radiofrequency characteristics such asimpedance and resonant frequency characteristics of the plasmaprocessing unit as a whole, and more specifically, the radiofrequencycharacteristics of the plasma processing chamber and the matchingcircuit have been neglected; consequently, no improvement in theelectrical consumption efficiency has been achieved when power of afrequency higher than approximately 13.56 MHz is employed, resulting indecrease in the deposition rate rather than improvement. Moreover,although the density of a generated plasma increases as the frequencyincreases, the density starts to decrease once its peak value isreached, eventually reaching a level at which glow-discharge is nolonger possible, thus rendering further increases in frequencyundesirable.

In a plasma processing apparatus and a plasma processing systemcomprising a plurality of plasma processing apparatuses, theradiofrequency characteristics of the plasma processing units includingthe matching circuits are defined by their mechanical dimensions such asshape. However, the components constituting the plasma processing unitinevitably have differences in size, etc., due to the mechanicaltolerance during manufacture. When these components are assembled tomake a plasma processing unit, the tolerance due to the assembly isadded to the tolerance in the mechanical dimensions. Furthermore, someportions of the plasma processing chamber may not be measurable afterassembly of the components; consequently, whether the plasma chamber asa whole has designed radiofrequency characteristics may not bequantitatively validated. Thus, means for examining the variation in theradiofrequency characteristics of the plasma processing chambers has notbeen available.

Thus, conventional plasma processing apparatuses suffer from thefollowing disadvantages.

Conventional plasma processing apparatuses and systems are not designedto eliminate the differences in electrical radiofrequencycharacteristics such as impedance and resonant frequency characteristicsamong the plasma processing units constituting the plasma processingapparatus or system. Thus, the effective power consumed in the plasmagenerating spaces of the plasma processing units and the density of thegenerated plasma vary between different plasma processing units.

As a consequence, uniformity in plasma process results may not beachieved when the same process recipe is applied to these plasmaprocessing units.

In order to obtain uniform plasma process results, external parameterssuch as gas flow, gas pressure, power supply, process time, and the likemust be compared with the process results according to Procedures (1) to(3) described above for each of the plasma processing units so as todetermine the correlation between them. However, the amount of data isenormous and it is impossible to completely carry out the comparison.

In order to validate and evaluate the operation of the plasma processingapparatus using Procedures (1) to (3) above, the plasma processingapparatus needs to be operated and deposited substrates need to beexamined by an ex-situ inspecting method requiring many steps.

Since such an inspection requires several days to several weeks to yieldevaluation results, the characteristics of the plasma-treated substratesprocessed during that period, supposing that the production line is notstopped, remain unknown during that period. If the performance of theplasma processing apparatus is poor, products not satisfying a requiredlevel may be manufactured. In this respect, a method for easilymaintaining the operation of the plasma processing apparatus at therequired level has been desired.

Moreover, when Procedures (1) to (3) described above are employed toinspect the plasma processing units constituting the plasma processingapparatus or system, the time required for adjusting the plasmaprocessing units so as to eliminate the difference in performance andvariation in processing among the plasma processing units to achieve thesame process results using the same process recipe may be months. Thetime required for such adjustment needs to be reduced. Also, the cost ofsubstrates for inspection, the cost of processing the substrates forinspection, the labor cost for workers involved with the adjustment, andso forth are significantly high.

SUMMARY OF THE INVENTION

In view of the above, the present invention aims to achieve thefollowing objects.

1. To achieve uniformity in AC resistances as the radiofrequencycharacteristics in the matching circuits of a plurality of plasmaprocessing units.

2. To achieve uniformity in the plasma process results among theplurality of plasma processing units by applying the same processrecipe.

3. To simplify the evaluation of the plurality of the plasma processingunits by making it unnecessary to determine process conditions based onthe relationships between an enormous amount of data on the plasmaprocessing units and the evaluation results obtained by Procedures (1)to (3) above.

4. To reduce the time required for adjusting the plasma processing unitsto achieve substantially the same process results using the same processrecipe.

5. To improve the planar uniformity of the plasma processing (the planardistribution of the layer thickness or the planar distribution of theprocess variation) and to improve the layer characteristics of thedeposited layers such as isolation voltage when applied to aplasma-enhanced CVD and a sputtering process.

6. To improve the power efficiency and to reduce the power loss so thatthe same processing rate and layer characteristics are obtained withless power.

7. To reduce the adjustment cost and the operation cost and to increasethe productivity.

8. To provide a plasma processing apparatus and system which can beeasily maintained at a suitable operation state.

In order to achieve the above-described goals, an aspect of the presentinvention provides a plasma processing apparatus comprising a pluralityof plasma processing units, each of the plurality of plasma processingunits comprising: a plasma processing chamber including an electrode forexciting a plasma; a radiofrequency generator for supplyingradiofrequency power to the electrode; and a matching circuit formatching the impedances of the plasma processing chamber and theradiofrequency generator, the matching circuit having an input terminalconnected to the radiofrequency generator, an output terminal connectedto the electrode, and a connection point provided between the inputterminal and the output terminal, the matching circuit being connectedto a ground potential portion via the connection point. Among theplurality of plasma processing units, a variation <RA> defined byequation (14A) below is set at a value within a predetermined range:<RA>=(RA _(max) −RA _(min))/(RA _(max) +RA _(min))  (14A)wherein RA_(max) and RA_(min) are the maximum and minimum values,respectively, of AC resistances RA in the matching circuits of theplurality of plasma processing units measured from theinput-terminal-side of the matching circuits. Also, a variation <RB>among the plurality of plasma processing units defined by equation (14B)below is set at a value within a predetermined range:<RB>=(RB _(max) −RB _(min))/(RB _(max) +RB _(min))  (14B)wherein RB_(max) and RB_(min) are the maximum and minimum values,respectively, of AC resistances RB in the matching circuits of theplurality of plasma processing units measured from theoutput-terminal-side of the matching circuits.

Thus, the difference in the radiofrequency characteristics, i.e., the ACresistances, affecting the impedance of the matching circuits of theplasma processing units can be minimized and the plasma processing unitscan be maintained within a predetermined range indicated by theimpedance characteristics. Consequently, uniformity in the effectivepower consumed in the plasma generating spaces of the plasma processingunits can be achieved.

When the same process recipe is applied to the plurality of the plasmaprocessing units, substantially the same plasma process results can beobtained. For example, when applied to a deposition apparatus, thedeposited layer will exhibit substantially the same layercharacteristics such as layer thickness, isolation voltage, and etchingrate.

The. AC resistances are the radiofrequency characteristics mainlydetermined by the mechanical structure of the device and are consideredto differ among the matching circuits of the plasma processing units. Bysetting the AC resistances within a predetermined range, the overallradiofrequency characteristics of the plasma processing units which havenot been concerned before are optimized, and stable plasma generationcan be achieved. Thus, the plasma processing units constituting theplasma processing apparatus or the system incorporating a plurality ofplasma processing apparatus stably operate and generate plasmas.

Moreover, examination of the correlation between the external parametersand the inspection results obtained through a conventional inspectionmethod requiring a step of inspecting the actually treated substratesusing an enormous amount of data in order to evaluate the processconditions is no longer necessary. Compared to a conventional inspectionmethod requiring the inspection of deposited substrates, the timerequired for adjusting the plasma processing units to minimize processvariations and to constantly achieve the same process results by usingthe same process recipe can be significantly reduced. The cost ofsubstrates for inspection, the cost of processing the substrates forinspection, and the labor cost for workers involved with the adjustmentcan also be reduced.

Preferably, the matching circuit is disconnected from the plasmaprocessing unit at the output terminal and at the input terminal, andthe AC resistance RA (input-terminal-side AC resistance RA) is measuredat a first measuring point corresponding to the input terminal. In thismanner, the resistance in the circuit extending from the first measuringpoint (input terminal) to the connection point on the ground potentialportion can be measured.

Thus, the difference in the radiofrequency characteristics of thematching circuits of the plasma processing units can be furtherminimized, and effective power consumed in the plasma generating spacesof the plasma processing units can be made substantially the same.Compared to the case excluding the matching circuit from the measuredregion, improved uniformity in the plasma process results using the sameprocess recipe can be achieved.

Preferably, the plasma processing unit further comprises aradiofrequency supplier disposed between the radiofrequency generatorand the input terminal of the matching circuit. Preferably, the matchingcircuit is disconnected from the plasma processing unit at the outputterminal and at an input end of the radiofrequency supplier, and the ACresistance RA is measured at a second measuring point corresponding tothe input end of the radiofrequency supplier. The difference in theradiofrequency characteristics of both the matching circuits and theradiofrequency suppliers among the plasma processing units can befurther minimized compared to the case where the radiofrequency supplieris excluded from the measured region. The uniformity in the effectivepower consumed in the plasma generating spaces of the plasma processingunits can be further enhanced, and highly uniform plasma process resultsusing the same process recipe can be achieved compared to the case inwhich the radiofrequency supplier is excluded from the measured region.

Preferably, the matching circuit is disconnected from the plasmaprocessing unit at the input terminal and at the output terminal of thematching circuit, and the AC resistance RB is measured at a thirdmeasuring point corresponding to the output terminal. The difference inthe radiofrequency characteristics of the matching circuits of theplasma processing units can be minimized, and the uniformity in theeffective power consumed in the plasma generating spaces of the plasmaprocessing units can be improved. When the same process recipe isapplied to these plasma processing units, uniformity in the plasmaprocess results is improved compared to the case in which the matchingcircuit is not included in the measured region.

Preferably, the plasma processing unit further comprises aradiofrequency feeder disposed between the output terminal of thematching circuit and the electrode. Preferably, the matching circuit isdisconnected from the plasma processing unit at the input terminal ofthe matching circuit and at an output end of the radiofrequency feeder,and the AC resistance RB is measured at a fourth measuring pointcorresponding to the output end of the radiofrequency feeder. Theradiofrequency characteristics in both the radiofrequency feeders (feedplates) and the matching circuits of the plurality of the plasmaprocessing units can be made uniform among these units, and theuniformity in the effective power consumed in the plasma generatingspaces of the plasma processing units can be further improved. When thesame process recipe is applied to these units, uniformity in the processresults is further improved compared to the case excluding theradiofrequency feeder (feed plate) from the measured region.

Preferably, the variations <RA> and <RB> are less than 0.5 to maintainthe uniformity in the plasma process results. When applied to adeposition apparatus, the variation in the layer thickness depositedusing the same process recipe among these plasma processing units can bemaintained within ±7%.

More preferably, the variations <RA> and <RB> are less than 0.4. Thedifference in the radiofrequency characteristics, i.e., the impedance,the AC resistance which is the real part of the impedance, the resonantfrequency characteristics, the capacitance, etc., of the plasmaprocessing units can be further minimized among these units. Thus, theplasma processing units can be maintained to a predetermined rangeindicated by the impedance characteristics, and the uniformity in theeffective power consumed in the plasma generating spaces of these plasmaprocessing units can be achieved.

As a result, substantially the same plasma process results can beobtained from these plasma processing units when the same process recipeis applied. When applied to a deposition apparatus, the deposited layerwill exhibit uniformity in the layer characteristics such as layerthickness, isolation voltage, etching rate, etc. More specifically, whenthe variations <RA> and <RB> are less than 0.4, the variation in thethickness of the layers deposited in the different plasma processingunits under the same process conditions can be kept within the range of±3%.

Preferably, the AC resistances RA and RB are values measured at a powerfrequency of the radiofrequency generator. The difference in theradiofrequency characteristics of the plasma processing units duringplasma generation can be minimized, and the plasma processing unitsduring plasma generation can be kept within a predetermined rangeindicated by the impedance. Moreover, the effective power consumed inthe plasma generating spaces of these units can be made substantiallyuniform.

Since resistance R is employed as the indicator, the radiofrequencycharacteristics at a power frequency can be further directly examinedcompared to the case in which the impedance Z which is a vector quantitydetermined by the resistance R and the reactance X is employed.

In this plasma processing apparatus, a radiofrequency characteristic Abetween the radiofrequency meter and the plasma processing units is setto be the same among these plasma processing units. Thus, the observedvalues of the AC resistance, impedance, etc., can be deemed equal to thevalue observed at the measuring point for each of the plasma processingunits without correction or conversion.

In order to adjust the radiofrequency characteristics between theradiofrequency meter and each of the plasma processing units to be equalto one another, coaxial cables of the same length connecting themeasuring points of the plasma processing units and the radiofrequencymeter may be used, for example.

The number of the plasma processing units in a plasma processingapparatus and the number of the plasma processing apparatuses in aplasma processing system can be set as desired.

Moreover, the settings of the radiofrequency characteristics, forexample, the AC resistances RA and RB, may differ among the plasmaprocessing units constituting the plasma processing apparatus if theplasma processing units are to perform different plasma processes usingdifferent process recipes.

Moreover, the present invention can be applied to a dual frequencyexcitation plasma-enhanced CVD unit having a first radiofrequencygenerator, a radiofrequency electrode connected to the firstradiofrequency generator, a first matching circuit for matching theimpedances of the first radiofrequency generator and the radiofrequencyelectrode, a radiofrequency-electrode-side matching box foraccommodating the first matching circuit, a second radiofrequencygenerator, a susceptor electrode disposed to oppose the radiofrequencyelectrode to support a substrate to be treated and connected to thesecond radiofrequency generator, a second matching circuit for matchingimpedances of the susceptor electrode and the second radiofrequencygenerator, and a susceptor-electrode-side matching box for accommodatingthe second matching circuit. In this unit, the radiofrequencycharacteristics, such as AC resistances RA and RB, of the secondmatching circuit can be adjusted in a manner similar to the matchingcircuit at the plasma excitation electrode side described above.

Preferably, the matching circuit further comprises at least oneconnection point for connecting the matching circuit to the groundpotential portion and the AC resistances RA and RB are measured for eachof the connection points by sequentially switching the connection pointsso that only one of the connection points is connected to the groundpotential portion. The variations <RA> and <RB> among the plurality ofthe plasma processing units are then defined by equations (14A) and(14B) and adjusted to be within the predetermined range for each of theconnection points. Thus, the effective power consumed in these plasmaprocessing units can be made substantially uniform.

Herein, since variations <RA> and <RB> are calculated for each of theconnection points, the largest <RA> and <RB> are adjusted to be withinthe predetermined range described above.

Another aspect of the present invention provides a performancevalidation system for a plasma processing apparatus or system. Theperformance validation system comprises: a customer terminal; anengineer terminal; and an information provider. The customer terminalrequests the information provider via a public line to view performanceinformation indicating the state of operation of the plasma processingapparatus or system described above which a customer purchased from anengineer. The engineer uploads the performance information through theengineer terminal. The information provider provides the performanceinformation uploaded through the engineer terminal to the customerterminal upon the request from the customer terminal. The performanceinformation is provided to a customer considering of purchasing theplasma processing apparatus or system as a basis for making thepurchasing decisions. During use of the plasma processing apparatus orsystem, the performance information is provided to inform the customerof the operation performance and maintenance status.

Preferably, the performance information contains information on thevariations <RA> and <RB> in the AC resistances RA and RB to provide auser with a basis for judging the performance of the plasma processingapparatus or system and to provide a customer considering purchasing theapparatus or system with a basis for making purchasing decisions.

The performance information may be output as a catalog or aspecification document.

Another aspect of the preset invention provides an inspection method fora plasma processing apparatus or system described above. The inspectionmethod comprises the steps of: inspecting whether a variation <RA> amongthe matching circuits of the plurality of plasma processing unitsdefined by equation (14A) described above is within a predeterminedrange; and inspecting whether a variation <RB> among the matchingcircuits of the plurality of plasma processing units defined by equation(14B) above is within a predetermined range. According to thisinspection method, whether the uniformity in the radiofrequencycharacteristics such as impedance, resonant frequency characteristics,and AC resistance is achieved among the plasma processing units can beinspected. Thus, the plasma processing units can be adjusted to bewithin a predetermined range indicated by the impedance characteristics,and the effective power consumed in the plasma generating spaces ofthese plasma processing units and the density of the plasma generated inthese plasma processing units can be made substantially uniform.

As a result, substantially uniform plasma process results can beachieved in these plasma processing units when the same process recipeis applied. That is, when a deposition process is performed using theseplasma processing units, the deposited layers will exhibit substantiallythe same layer characteristics such as layer thickness, isolationvoltage, and etching rate.

The electrical radiofrequency characteristics of each of the plasmaprocessing units and the matching circuits therein are defined by theshape, that is, by the mechanical dimensions. However, the dimensions ofeach of the components constituting the plasma processing unit vary dueto the mechanical tolerance during the manufacturing process. The plasmaprocessing units made by assembling such components inevitably havevariations due to both the mechanical tolerance and the assemblytolerance. No method for determining whether the overall plasma chamberhas the designed electrical radiofrequency characteristics has beenavailable since some portions are not measurable after assembly of thecomponents. By employing the inspection method of the present invention,the performance of the plasma processing units can be inspectedquantitatively and the variation in the radiofrequency characteristicscan be examined without measuring the mechanical dimensions. Theinspection method is applicable to a plasma processing unit of which themechanical dimensions are not measurable.

In this inspection method, the input-terminal-side AC resistance RA ofthe matching circuit may be measured at a first measuring pointcorresponding to the input terminal of the matching circuit whiledisconnecting the matching circuit from the plasma processing unit atthe output terminal and at the input terminal. Thus, the difference inthe radiofrequency characteristics among the plurality of the plasmaprocessing units including the matching circuits can be minimized, theeffective power consumed in the plasma generating spaces of these plasmaprocessing units can be made substantially uniform, and higheruniformity in the plasma process results is achieved compared to thecase where the radiofrequency characteristics of the matching circuitare not measured.

Instead of the first measuring point described above, a second measuringpoint may be used to measure the input-terminal-side AC resistance RA ofthe matching circuit. The second measuring point corresponds to an inputend of a radiofrequency supplier disposed between the radiofrequencygenerator and the input terminal of the matching circuit. Theinput-terminal-side AC resistance RA is measured at the second measuringpoint while disconnecting the matching circuit from the plasmaprocessing unit at the output terminal and at the input end of theradiofrequency supplier. Thus, the radiofrequency characteristics of theplasma processing units including the radiofrequency suppliers can bemade substantially uniform among these plasma processing units, theeffective power consumed in the plasma generating spaces of the plasmaprocessing units can be made substantially uniform, and the higheruniformity in the plasma process results can be achieved compared to thecase where the radiofrequency supplier is not included in the measureregion.

In this inspection method, the matching circuit may be disconnected fromthe plasma processing unit at the input terminal and at the outputterminal of the matching circuit, and the AC resistance RB may bemeasured at a third measuring point corresponding to the outputterminal. Thus, the radiofrequency characteristics of the plasmaprocessing units can be made substantially uniform among these plasmaprocessing units, the effective power consumed in the plasma generatingspaces of the plasma processing units can be made substantially uniform,and higher uniformity in the plasma process results can be achievedcompared to the case where the matching circuit is not included in themeasure region.

Instead of the third measuring point described above, a fourth measuringpoint may be used to measure the output-terminal-side AC resistance RBof the matching circuit. The fourth measuring point corresponds to anoutput end of a radiofrequency supplier disposed between the outputterminal of the matching circuit and the electrode. Theoutput-terminal-side AC resistance RB is measured while disconnectingthe matching circuit from the plasma processing unit at the inputterminal of the matching circuit and at the output end of theradiofrequency feeder. Thus, the difference in the radiofrequencycharacteristics among these plasma processing units including theradiofrequency feeders (feed plates) can be minimized, the effectivepower consumed in the plasma generating spaces of these plasmaprocessing units can be made substantially uniform, and higheruniformity in the plasma process results can be achieved using the sameprocess recipe compared to the case where the radiofrequency feeder isnot included in the measured region.

In this inspection method, both the predetermined ranges are preferablyless than 0.5. In this manner, the uniformity in the plasma process,i.e., whether the variation among these plasma processing units in thethickness of the layers deposited under the same process conditions ismaintained within the range of ±7%, can be inspected.

In this inspection method, the AC resistances RA and RB are valuesmeasured at a power frequency of the radiofrequency generator. Thus,inspection of whether the variation in the radiofrequencycharacteristics of the plasma processing units in the plasma generatingstate is eliminated can be conducted. The inspection of whether theplasma processing units in the plasma generating state are maintained ina predetermine range indicated by impedance characteristics, forexample, can also be conducted. As a result, the effective powerconsumed in the plasma generating spaces of the plasma processing unitscan be made substantially uniform among these plasma processing units.

Since resistance R is employed as the indicator of the radiofrequencycharacteristics, the radiofrequency characteristics at a power frequencycan be further directly examined compared to the case in which theimpedance Z which is a vector quantity determined by the resistance Rand the reactance X is employed.

In this inspection method, a radiofrequency characteristic between theradiofrequency meter and the plasma processing units is set to be thesame among these plasma processing units. Thus, the observed values ofthe AC resistance, impedance, etc., can be deemed equal to the valueobserved at the measuring point for each of the plasma processing unitswithout correction or conversion. Thus, the inspection can be performedfurther efficiently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an overall structure of a plasmaprocessing apparatus according to a first embodiment of the presentinvention;

FIG. 2 is a cross-sectional view showing an overall structure of aplasma processing unit shown in FIG. 1;

FIG. 3 is a schematic diagram of a matching circuit of the plasmaprocessing unit shown in FIG. 2;

FIG. 4 is a schematic circuit diagram for describing parasiticresistances in the matching circuit shown in FIG. 3;

FIG. 5 is a schematic circuit diagram for describing parasiticresistances in the matching circuit shown in FIG. 3;

FIG. 6 is a vertical sectional view of a laser annealing unit shown inFIG. 1;

FIG. 7 is a vertical sectional view of an annealing unit shown in FIG.1;

FIG. 8 is a perspective view of a probe of an impedance meter;

FIG. 9 is a schematic diagram showing the connections of the probe ofthe impedance meter shown in FIG. 8;

FIG. 10 is a schematic diagram showing an overall structure of a plasmaprocessing apparatus according to a second embodiment of the presentinvention;

FIG. 11 is a cross sectional view of a plasma processing unit shown inFIG. 10;

FIG. 12 is a schematic diagram showing a matching circuit of the plasmaprocessing unit shown in FIG. 11;

FIG. 13 is a perspective circuit diagram for describing parasiticresistances in the matching circuit shown in FIG. 12;

FIG. 14 is a perspective circuit diagram for describing parasiticresistances in the matching circuit shown in FIG. 12;

FIG. 15 is a schematic diagram showing an overall structure of a plasmaprocessing unit according to a third embodiment of the presentinvention;

FIG. 16 is a schematic diagram showing a matching circuit of the plasmaprocessing unit shown in FIG. 15;

FIG. 17 is a schematic circuit diagram describing parasitic resistancesin the matching circuit shown in FIG. 16;

FIG. 18 is a schematic diagram showing a matching circuit of a plasmaprocessing unit according to a fourth embodiment of a plasma processingapparatus;

FIG. 19 is a schematic circuit diagram describing parasitic resistancesin the matching circuit shown in FIG. 18;

FIG. 20 is a schematic circuit diagram describing parasitic resistancesin the matching circuit shown in FIG. 18;

FIG. 21 is a schematic diagram showing an overall structure of a plasmaprocessing system according to fifth embodiment of the presentinvention;

FIG. 22 is a schematic diagram showing an overall structure of theplasma processing apparatuses according to the first to fifthembodiments;

FIG. 23 is a schematic diagram showing an overall structure of a plasmaprocessing apparatus of another embodiment;

FIG. 24 is a schematic diagram showing an overall structure of a plasmaprocessing apparatus of yet another embodiment:

FIG. 25 is a diagram illustrating the configuration of a performancevalidation system for a plasma processing apparatus according sixthembodiment of the present invention;

FIG. 26 is a flowchart illustrating a process of providing “performanceinformation” executed at a server S in the performance validation systemfor the plasma processing apparatus of the sixth embodiment of thepresent invention;

FIG. 27 is a plan view showing a structure of a main page CP related tothe performance validation system for the plasma processing apparatus;

FIG. 28 is a plan view showing a structure of a subpage CP1 related tothe performance validation system for the plasma processing apparatus;

FIG. 29 is a plan view showing a structure of a main page CP2 related tothe performance validation system for the plasma processing apparatus;

FIG. 30 is a plan view showing a structure of a subpage CP3 related tothe performance validation system for the plasma processing apparatus;

FIG. 31 is a plan view showing a structure of a subpage CP4 related tothe performance validation system for the plasma processing apparatus;

FIG. 32 is a flowchart showing an inspection method for a plasmaprocessing apparatus according to the present invention;

FIG. 33 is a schematic diagram showing a conventional plasma processingunit; and

FIG. 34 is a schematic diagram showing another conventional plasmaprocessing unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

Now, a first embodiment of a plasma processing apparatus and aperformance validation system therefor according to the presentinvention is described with reference to the drawings.

FIG. 1 is an illustration showing the overall structure of a plasmaprocessing apparatus 71 according to the first embodiment. The plasmaprocessing apparatus 71 comprises a plurality of processing unitssuitable for consecutive processing, for example, from depositing apolysilicon film as a semiconductor active film to depositing a gateinsulating film of top-gate TFTs.

In this plasma processing apparatus 71, five processing units, oneloading chamber 73, and one unloading chamber 74 are continuouslyarranged around a substantially heptagonal transfer chamber 72. The fiveprocessing units are a first deposition unit 75 for depositing anamorphous silicon film, a second deposition unit 76 for depositing asilicon oxide film, and a third deposition unit 77 for depositing asilicon nitride film, a laser annealing unit 78 for annealing aprocessed substrate after deposition, and an annealing unit 79 forperforming a heat treatment of the processed substrate.

The first, second, and third deposition units 75, 76, and 77 havingsubstantially the same structure may be used either for depositingdifferent types of films or for performing the same treatment using thesame process recipe. As is described in detail below, an AC resistanceRA measured from the input terminal side of a matching circuit 2A (FIG.2) of each of the first, second, and third deposition units 75, 76, and77, is set so that a variation <RA> in AC resistance RA among theseunits defined by relationship (14A) below wherein RA_(max) is themaximum value and RA_(min) is the minimum value is within apredetermined range.<RA>=(RA _(max) −RA _(min))/(RA _(max) +RA _(min))  (14A)

Moreover, an AC resistance RB measured from the output terminal side ofthe matching circuit 2A of each of the first, second, and thirddeposition units 75, 76, and 77 is set so that a variation <RB> in ACresistance RB among these units defined by relationship (14B) belowwherein RB_(max) is the maximum value and RB_(min) is the minimum valueis within a predetermined range.<RB>=(RB _(max) −RB _(min))/(RB _(max) +RB _(min))  (14B)

Now, the structure of the plasma processing unit will be described usingthe first deposition unit 75 as an example.

FIG. 2 is a cross-sectional view showing an overall structure of theplasma processing unit. FIG. 3 illustrates a matching circuit of theplasma processing unit shown in FIG. 2.

The plasma processing unit (first deposition unit) 75 is of asingle-frequency excitation type and performs a plasma process such as aCVD process, a sputtering process, a dry etching process, and an ashingprocess. Referring to FIG. 2, the first deposition unit 75 comprises aplasma processing chamber 60 having parallel plate electrodes 4 and 8for exciting a plasma, a radiofrequency generator 1 connected to theelectrode 4, and the matching circuit 2A for matching the impedances ofthe plasma processing chamber and the radiofrequency generator 1.

To describe in greater detail, in the first deposition unit 75, theplasma excitation electrode 4 coupled to the radiofrequency generator 1and a shower plate 5 are provided above the plasma processing chamber60, and the susceptor electrode 8 for receiving a substrate 16 isdisposed in the lower portion of the plasma processing chamber 60 so asto oppose the shower plate 5, as shown in FIGS. 2 and 3. The plasmaexcitation electrode 4 is connected to the radiofrequency generator 1through a feed plate 3 and the matching circuit 2A. The plasmaexcitation electrode 4 and the feed plate 3 are covered by a chassis 21,and the matching circuit 2A is accommodated inside a matching box 2.

A silver-plated copper plate 50 to 100 mm in width, 0.5 mm in thickness,and 100 to 300 mm in length is used as the feed plate 3. The feed plate3 is detachably attached to an output terminal of a tuning capacitor 24in the matching circuit 2A and to the plasma excitation electrode 4 byfixing means such as screws.

An annular projection 4 a is provided on the bottom face of the plasmaexcitation electrode 4. The projection 4 a comes into contact with theshower plate 5 having many holes 7 under the plasma excitation electrode4. The plasma excitation electrode 4 and the second ferromagnetic layer5 define a space 6 to which a gas feeding tube 17 extending through theside wall of the chassis 21 and through the plasma excitation electrode4 is connected.

The gas feeding tube 17 is composed of a conductor, and an insulator 17a is provided midway inside the chassis 21 to insulate between theplasma excitation electrode 4 and the gas source.

The gas introduced from the gas feeding tube 17 is fed into the plasmaprocessing chamber 60 surrounded by a chamber wall 10 through the manyholes 7 in the shower plate 5. The chamber wall 10 and the plasmaexcitation electrode 4 are isolated from each other by an insulator 9.Note that in FIG. 2, the exhaust system connected to the plasmaprocessing chamber 60 is omitted from the drawing.

The susceptor electrode 8 for receiving the substrate 16 disposed in theplasma processing chamber 60 is of a disk shape and functions as anotherplasma excitation electrode.

A shaft 13 is joined to the bottom center of the susceptor electrode 8and extends through a chamber bottom 10A. The lower end of the shaft 13and the center portion of the chamber bottom 10A are hermeticallyconnected by a bellows 11. The susceptor electrode 8 and the shaft 13are vertically movable by the bellows 11 to control the distance betweenthe plasma excitation electrode 4 and the susceptor electrode 8.

Since the susceptor electrode 8 and the shaft 13 are connected to eachother as in FIG. 2, the susceptor electrode 8, the shaft 13, the bellows11, the chamber bottom 11A, and the chamber wall 10 have the same DCpotential. Moreover, because the chamber wall 10 and the chassis 21 areconnected to each other, the chamber wall 10, the chassis 21, and thematching box 2 have the same DC potential.

The matching circuit 2A in most cases includes a plurality of passiveelements in order to adjust impedance in response to the change in theplasma state inside the plasma processing chamber 60.

As shown in FIGS. 2 and 3, the matching circuit 2A is disposed betweenthe radiofrequency generator 1 and the feed plate 3 and comprises as thepassive elements an inductance coil 23, a tuning capacitor 24 comprisingan air-variable capacitor, and a load capacitor 22 comprising avacuum-variable capacitor. The matching circuit 2A also includesconductors R1 and R2 made of copper plates for connecting these passiveelements.

The conductor R1, the inductance coil 23, and the tuning capacitor 24are connected in series in that order from the input terminal side ofthe matching circuit 2A to the output terminal side of the matchingcircuit 2A. The load capacitor .22 is connected to these elements inparallel from a branching point B1 provided between the conductor R1 andthe inductance coil 23. The inductance coil 23 and the tuning capacitor24 are directly connected to each other without a conductor, and one endof the load capacitor 22 is connected to the matching box 2 (groundpotential portion) through the conductor R2 at a connection point BP1.

Herein, the tuning capacitor 24 is the last stage among the passiveelements constituting the matching circuit 2A, and the output terminalof the tuning capacitor 24 is the output terminal of the matchingcircuit 2A. The tuning capacitor 24 is connected to the plasmaexcitation electrode 4 through the feed plate 3.

The matching box 2 is connected to a shielding line of a feed line(radiofrequency supplier) 1A which is a coaxial cable. Because theshielding line is DC grounded, the susceptor electrode 8, the shaft 13,the bellows 11, the chamber bottom 10A, the chassis 21, and the matchingbox 2 are all set to the ground voltage. The above-described one end ofthe load capacitor 22 is thereby also DC grounded.

In the first deposition unit 75, radiofrequency power of 13.56 MHz ormore, for example, 13.56 MHz, 27.12 MHz, and 40.68 MHz, may be used togenerate a plasma between the plasma excitation electrode 4 and thesusceptor electrode 8 to perform a plasma process such as a CVD process,a dry etching process, and an ashing process on the substrate 16 placedon the susceptor electrode 8.

During processing, radiofrequency power from the radiofrequencygenerator 1 is supplied to the feed line 1A which is a coaxial cable,the matching circuit 2A, the feed plate 3, and the plasma excitationelectrode 4. As for the path of the radiofrequency current, the currentafter going through these elements flows into the plasma processingchamber 60 and to the susceptor electrode 8, the shaft 13, the susceptorshield 12, the bellows 11, the chamber bottom 10A, and the chamber wall10. Subsequently, the current returns to the ground position of theradiofrequency generator 1 via chassis 21, the matching box 2, and theshielding line of the feed line 1A.

AC resistances RA and RB of the matching circuit 2A as theradiofrequency characteristics of the first deposition unit 75 of thisembodiment will now be described.

The AC resistance of the matching circuit 2A measured from the inputterminal side of the matching circuit 2A is the AC resistance RA and theAC resistance of the matching circuit 2A measured from the outputterminal side of the matching circuit 2A is the AC resistance RB. Thefrequency for measuring the AC resistance is selected from the range ofabout 1 to 100 MHz including the power frequency of the radiofrequencygenerator 1. Preferably, a frequency corresponding to a power frequencyf_(e), i.e., 13.56 MHz, 27.12 MHz, or 40.68 MHz, is used as thefrequency for measurement.

The AC resistances RA and RB are radiofrequency characteristics mainlydetermined by the structure of the matching circuit 2A and are measuredas in FIGS. 4 and 5.

FIGS. 4 and 5 are schematic circuit diagrams showing parasiticresistance in the matching circuit 2A.

The measured region in the matching circuit 2A according to thisembodiment is from a point PR3 corresponding to the position of theinput terminal of the passive element located at the first stage of thematching circuit 2A to a point PR which corresponds to the position ofthe output terminal of the passive element located at the last stage ofthe matching circuit 2A. As shown in FIG. 4, during the measurement, thefeed line 1A is detached from the matching circuit 2A, and the feedplate 3 is detached from the matching circuit 2A at the point PRcorresponding to the position of the output terminal of the tuningcapacitor 24 by removing screws connecting the matching circuit 2A tothe feed plate 3.

As shown by broken lines in FIG. 4, a probe 105 of an impedance meter(radiofrequency characteristics measuring instrument) AN is connected toa ground position on the matching box 2 (ground potential portion) andto the point PR3. The frequency oscillated by the impedance meter AN isthen set to a frequency in the range of 1 to 100 MHz, for example, afrequency equal to the power frequency f_(e) such as about 40.68 MHz, inorder to determine the vector quantity (Z, θ) of the impedance in theabove-described measured region of the matching circuit 2A. The realpart in the complex expression of the impedance is calculated therefromto define the AC resistance RA.

As shown in FIG. 4, the probe 105 comprises a conductive line 110, aninsulation coating 112 coating the conductive line 110, and a peripheralconductor 111 covering the insulation coating 112. The probe 105 isconnected to the impedance meter AN via a coaxial cable. The conductiveline 110 is connected to the point PR3, and the peripheral conductor 111is connected to the ground position which is the center of the upperface of the matching box 2.

Each of the inductance coil 23, the tuning capacitor 24, the loadcapacitor 22, and the conductors R1 and R2 constituting the matchingcircuit 2A has AC resistance and inductance. The AC resistance isdefined by these resistances and inductances, and the parasiticresistance that exists in the circuit when the AC current is introduced.

As shown in FIG. 4, the radiofrequency elements contributing to theinput-terminal-side AC resistance RA of the matching circuit 2A lying inthe circuit indicated by an arrow I_(RA) extending from the point PR3 tothe connection point BP1 via the branching point B1 are as follows:

Parasitic resistance R_(R1) in the conductor R1

Inductance L_(R1) in the conductor R1

Capacitance C_(L) of the load capacitor 22

Parasitic resistance R_(R2) in the conductor R2

Inductance L_(R2) in the conductor R2

As shown in FIG. 4, the parasitic resistance R_(R1) in the conductor R1and the parasitic resistance R_(R2) in the conductor R2 are measured asthe input-terminal-side AC resistance RA of the matching circuit 2A inthis embodiment.

Here, the parasitic resistance R_(R1) includes parasitic resistances-existing in the circuit I_(RA) during measurement of theinput-terminal-side AC resistance RA but not being illustrated in thedrawing, such as a resistance from the branching point B1 to the loadcapacitor 22.

The output-terminal-side AC resistance RB of the matching circuit 2A ismeasured in a manner similar to the above description. As shown in FIG.5, the probe 105 of the impedance meter AN is attached to a groundposition of the matching box 2 (ground potential portion) and to thepoint PR. The frequency oscillated by the impedance meter. AN is thenset to a frequency in the range of 1 MHz to 100 MHz, for example, inorder to determine the vector quantity (Z, θ) of the impedance in theabove-described measured region of the matching circuit 2A. The realpart in the complex expression of the impedance is calculated therefromto define the AC resistance RB.

As shown in FIG. 5, the conductive line 110 of the probe 105 isconnected to the point PR, and the peripheral conductor 111 of the probe105 is connected to a ground position of the matching box 2.

As shown in FIG. 5, the radiofrequency elements contributing to theoutput-terminal-side AC resistance RB of the matching circuit 2A lyingon the path indicated by an arrow I_(RB) extending from the point PR tothe ground potential portion via the branching point B1 are as follows:

Capacitance C_(LT) of the tuning capacitor 24

Parasitic resistance R_(LT) in the inductance coil 23

Inductance L_(T) in the inductance coil 23

Capacitance C_(L) of the load capacitor 22

Parasitic resistance R_(R2) in the conductor R2

Inductance L_(R2) in the conductor R2

Among these elements, as shown in FIG. 5, the parasitic resistanceR_(LT) in the inductance coil 23 and the parasitic resistance R_(R2) inthe conductor R2 are measured as the output-terminal-side AC resistanceRB of the matching circuit 2A.

Note that the parasitic resistance R_(LT) includes parasitic resistancesexisting in the circuit I_(RB) during measurement of theoutput-terminal-side AC resistance RB but not being illustrated in thedrawing, such as a resistance from the branching point B1 to the loadcapacitor 22.

In the matching circuit 2A of the first deposition unit 75, theinput-terminal-side AC resistance RA and the output-terminal side ACresistance RB are adjusted to fall within a predetermined range suitablefor operation of the first deposition unit 75.

Examples of a method for optimizing the AC resistances RA and RB are:

(1) Adjusting the shape, i.e., the length and the width, of the copperplates constituting the conductors R1 and R2.

(2) Adjusting the state of assembly of the copper plates constitutingthe conductors R1 and R2.

(3) Plating the copper plates constituting the conductors R1 and R2 withsilver.

In the plasma processing apparatus 71 of this embodiment, the seconddeposition unit 76 and the third deposition unit 77 have substantiallythe same structure as that of the first deposition unit 75. The ACresistances RA and RB as the radiofrequency characteristics of thesecond deposition unit 76 and the third deposition unit 77 are also setas in the above description.

More specifically, in the first, second, and third deposition units 75,76, and 77, the AC resistances RA and RB are measured while setting thepower frequency f_(e) at 40.68 MHz.

The AC resistances RA and RB are the radiofrequency characteristicsmainly determined by the mechanical structure of the circuit and aredifferent among different plasma processing units.

By setting the AC resistances RA and RB in the matching circuit 2A ofthe first deposition unit 75, a power loss due to resistance whichaffects the effective power consumption in the plasma generation spacebetween the plasma excitation electrode 4 and the susceptor electrode 8can be optimized. Here, an impedance Z (Ω) and an inductance X are givenby equations (11A) below:Z=R+jX X=f (ω, L, C)  (11A)wherein j which stands for j²=−1 is the imaginary unit and ω whichstands for ω=2πf_(e) wherein f_(e) is a power frequency is an angularfrequency. The impedance X is expressed by a function of ω, L, and C.R=Re(Z)  (11B)

As shown in equation (11B) above, because the real part of the impedanceZ is an AC resistance R, the power loss at the matching circuit 2Alocated at a position closer to the radiofrequency generator 1 than arethe electrodes 4 and 8 can be optimized by adjusting the AC resistanceRA and RB in the matching circuit 2A. As a result, the resistance Rwhich significantly affects the voltage drop and yields a decrease inplasma generating energy can be optimized, thereby preventing anincrease in effective power loss.

Now, the process for setting the variation in the input-terminal-side ACresistance RA and the output-terminal-side AC resistance RB within apredetermined range will be described with reference to FIG. 32.

First, RA and RB of the matching circuit are measured for each of theplasma processing units (Step P1). Herein, RA₇₅, RA₇₆, and RA₇₇represent the input-terminal-side AC resistances RA of the firstdeposition unit 75, the second deposition unit 76, and the thirddeposition unit 77, respectively, and RB₇₅, RB₇₆, and RB₇₇ represent theoutput-terminal-side AC resistances RB of the first deposition unit 75,the second deposition unit 76, and the third deposition unit 77,respectively.

Next, a variation <RA> in the input-terminal-side AC resistance RA amonga plurality of plasma processing units 75, 76 and 77 is defined by-equation (14A) below relative to the maximum value RA_(max) and theminimum value RA_(min) selected from among RA₇₅, RA₇₆, and RA₇₇ (StepP2):<RA>=(RA _(max) −RA _(min))/(RA _(max) +RA _(min))  (14A)

The value <RA> defined by equation (14A) is then adjusted to be smallerthan 0.5 (Steps P3 and P4). In adjusting the input-terminal-side ACresistance RA, the above-described methods (1) to (3) for optimizing theAC resistance can be applied.

Next, a variation <RB> in the output-terminal-side AC resistance RBamong a plurality of plasma processing units 75, 76 and 77 is defined asequation (14B) below relative to the maximum value RB_(max) and theminimum value RB_(min) selected from among RB₇₅, RB₇₆, and RB₇₇ (StepP5):<RB>=(RB _(max) −RB _(min))/(RB _(max) +RB _(min))  (14B)

The value <RB> defined by equation (14B) is then adjusted to be smallerthan 0.5 (Steps P6 and P7). In adjusting the output-terminal-side ACresistance RB, the above-described methods (1) to (3) for optimizing theAC resistance can be applied.

In these processing units 75, 76, and 77, the substrate 16 is placed onthe susceptor electrode 8, and the radiofrequency generator 1 supplies aradiofrequency power to both the plasma excitation electrode 4 and thesusceptor electrode 8 while a reactive gas is fed into the plasmaprocessing chamber 60 from the gas feeding tube 17 via the holes 7 togenerate a plasma for forming an amorphous silicon layer, a siliconoxide layer, or a silicon nitride layer on the substrate 16.

Referring to FIG. 6, the laser annealing unit 78 is provided with alaser light source 81 on the upper wall 80 and a stage 82 for receivingthe substrate 16 to be treated on the bottom wall of the chamber. Thestage 82 is horizontally movable in the orthogonal X and Y directions.Spot laser light 83 (shown by chain lines) is emitted from an aperture81 a of a laser light source 81, while the stage 82 supporting thesubstrate 16 horizontally moves in the X and Y directions so that thelaser light 83 scans the entire surface of the substrate 16. Examples ofthe laser light sources 81 are gas lasers using halogen gases, such asXeCl, ArF, ArCl, and XeF.

The laser annealing unit 78 may be of any configuration as long as thespot laser beam from the laser light source can scan the entire surfaceof the substrate to be treated. Also, in this case, gas lasers usinghalogen gases, such as XeCl, ArF, ArCl, and XeF can be used as laserlight sources. Alternatively, other laser light sources such as a YAGlaser may be used depending on the type of the layer to be annealed.Laser annealing may be pulsed laser annealing or continuouslyoscillating laser annealing. The annealing chamber may be of, forexample, a multistage electrical furnace type.

As shown in FIG. 7, the annealing unit 79 is of a multistage electricalfurnace type. In the annealing unit 79, a plurality of substrates 16 isplaced on heaters 85 which are vertically arranged in the chamber. Theseheaters 85 are energized to heat the substrates 16. A gate valve 86 isprovided between the annealing unit 79 and the transfer chamber 72.

With reference to FIG. 1, the loading chamber 73 and the unloadingchamber 74 are provided with a loading cassette and an unloadingcassette, respectively, which are detachable from these chambers. Theloading cassette can accommodate a plurality of unprocessed substrates16 whereas the unloading cassette can accommodate a plurality ofprocessed substrates 16. A transfer robot 87 as means for transferringthe substrates 16 is placed in the transfer chamber 72 which issurrounded by the processing units, the loading chamber 73, and theunloading chamber 74. The transfer robot 87 is provided with an arm 88thereon. The arm 88 has an extendable and retractable link mechanism andcan rotate and vertically move. The substrate 16 is supported andtransferred with the end of the arm 88.

In this plasma processing apparatus 71, the operations of the componentsare automatically controlled by a control section, whereas variousprocessing conditions, such as layer deposition conditions, annealingconditions, and heating conditions, and process sequences are set by anoperator. In operating the plasma processing apparatus 71, untreatedsubstrates 16 are loaded into the loading cassette, and are transferredfrom the loading cassette to each processing chamber by the transferrobot 87 based on the starting operation by the operator. After thesubstrates 16 are automatically and sequentially processed in eachchamber, the substrates 16 are placed in the unloading cassette by thetransfer robot 87.

In this plasma processing apparatus 71 and the inspection methodtherefor, a variation defined by equation (10A) between the maximumvalue and minimum value among the values of the input-terminal-side ACresistances RA measured at the point PR3 of the matching circuit 2A ofeach of the plasma processing units 75, 76, and 77 and a variationdefined by equation (10B) between the maximum value and minimum valueamong the values of the output-terminal-side AC resistances RB measuredat the point PR of the matching circuit 2A of each of the plasmaprocessing units 75, 76, and. 77 are set at a value smaller than 0.5.Thus, differences in radiofrequency characteristics among the first,second, and third deposition units 75, 76, and 77 can be minimized, andthe state of the first, second, and third deposition units 75, 76, and77 can be maintained within a predetermined range indicated by theimpedance characteristics. As a result, the effective power consumed inthe plasma space can be adjusted to be substantially the same among thefirst, second, and third deposition units 75, 76, and 77.

Moreover, substantially the same plasma process results can be obtainedby applying the same process recipe to the first, second, and thirddeposition units 75, 76, and 77 and the layers formed in these unitshave substantially the same layer characteristics such as layerthickness, isolation voltage, and etching rate. More particularly, an<RA> and <RB> less than 0.5 among these units will give a variation inthe layer thickness in the range of ±7%.

Accordingly, the variation in the planar uniformity of the plasmaprocessing due to the mechanical difference in the plasma processingunits can be minimized. When the present embodiment is applied to adeposition process as above, the variation in planar uniformity of thelayer thickness distribution due to the mechanical difference amongdifferent deposition units can be minimized.

In a deposition process such as a plasma enhanced CVD process or asputtering process, the variation among the first, second, and thirddeposition units 75 to 77 in improvements in the conditions of thedeposited layers, i.e., the layer characteristics such as the isolationvoltage, resistance against etchants, and the density (hardness) of thedeposited layers can be minimized.

The density of the deposited layer can be expressed in terms ofresistance against a BHF solution as an etchant, for example.

Thus, the overall radiofrequency characteristics of the plasmaprocessing apparatus 71 which has not been considered before can beadjusted, and stable plasma generation can be achieved. The plasmaprocessing units 75 to 77 thereby achieve stable and uniform operation.

Also, examination of the correlation between the external parameters andthe inspection results obtained through a conventional inspection methodrequiring a step of inspecting the actually treated substrates using anenormous amount of data in order to evaluate the process conditions isno longer necessary.

Compared to the conventional inspection method requiring the inspectionof deposited substrates, the time required for adjusting the plasmaprocessing units 75 to 77 to minimize process variation and toconstantly achieve the same process results by using the same processrecipe can be significantly reduced by measuring AC resistances RA andRB in the matching circuit 2A which directly supplies electric power tothe plasma processing units 75 to 77. Moreover, the plasma processingapparatus 71 can be directly evaluated in situ within a shorter periodof time, instead of by a two-step process of first evaluating thetreated substrate and then evaluating the operation of the plasmaprocessing apparatus. When the conventional inspection method requiringlayer deposition on substrates is performed to determine the processrecipe upon the installation of the plasma processing apparatus of thisembodiment, such an inspection may be performed in only one of theplasma processing units since the plasma processing units 75 to 77 havethe same radiofrequency characteristics. In the maintenance of theplasma processing apparatus, actual layer deposition is not requiredbecause the radiofrequency characteristics of the plasma processingunits are controlled within the predetermined range. Thus, the plasmaprocessing units, which have been inspected independently according tothe conventional art, can be inspected simultaneously

Thus, the inspection method of this embodiment does not require theproduction line to be stopped for days or weeks to validate and evaluatethe operation of the plasma processing apparatus, and the productivityof the manufacturing line can be increased thereby. Moreover, the costof substrates for inspection, the cost of processing the substrates forinspection, and the labor cost for workers involved with the adjustmentcan be reduced.

The overall radiofrequency characteristics of the plasma processingunits 75 to 77, which have not been considered before, can be optimizedby adjusting the AC resistances RA and RB in the matching circuit 2A,the plasma processing units 75 to 77 thus achieving stable operations.Power with a frequency higher than a frequency conventionally employed,i.e., about 13.56 MHz, can be effectively introduced from theradiofrequency generator 1 to the plasma generating space between theplasma excitation electrode 4 and the susceptor electrode 8. When powerwith the same frequency conventionally used is supplied, the effectivepower consumed in the plasma generating space can be increased comparedto conventional plasma processing apparatuses.

As a result, the processing rate can be improved by increasing theplasma excitation frequency. When applied to a plasma-enhanced CVDprocess, the deposition rate can be improved.

The impedance characteristic of the plasma processing units 75 to 77 canalso be measured by using a fixture shown in FIG. 8 comprising aplurality of conductive wires 101 a to 101 h, each having the sameimpedance, and a probe attachment 104, to which one end of each of theplurality of conductive wires 101 a to 101 h is attached.

The probe attachment 104 is formed, for example, by shaping a 50 mm×10mm×0.5 mm copper plate into a clamping portion 106 and a ring portion.The diameter of the ring portion is determined so that the ring portionis attachable to the circumference of the probe 105. One end of each ofthe conductive wires 101 a to 101 h is soldered to the probe attachment104 to be electrically connected thereto.

Terminals (attachments) 102 a to 102 h which are attachable to anddetachable from an object to be measured are installed at the other endsof the conductive wires 101 a to 101 h.

In using this fixture, the probe 105 is inserted into the ring portionof the probe attachment 104, and the probe 105 and the probe attachment104 are clamped by the clamping portion 106. The conductive wires 101 ato 101 h are detachably screwed to the measured object in asubstantially symmetrical manner about a point through the terminals 102a to 102 h, as shown in FIG. 9.

The conductive wires 101 a to 101 h may be made of, for example,aluminum, copper, silver, or gold, or may be plated by silver or goldhaving a thickness of 50 μm or more.

The method for measuring impedance using this fixture is now explainedwith reference to FIG. 9.

First, in measuring the input-terminal-side AC resistance RA, theradiofrequency generator 1 and the feed plate 3 are detached from thematching box 2. The conductive line 110 of the probe 105 of the fixtureis then connected to the point PR3. The terminals 102 a to 102 hconnected to the conductive wires 101 a to 101 h of the fixture arescrewed to the matching box 2 in a substantially symmetrical mannerabout the point PR3 using screws 114. After the fixture is set as above,a measuring signal is supplied to the conductive line 110 to measure theimpedance of the paths in the matching circuit 2A of each of the plasmaprocessing units 75 to 77.

In this manner, a uniform current flows to the measuring objectregardless of the size of the measuring object or the distance betweentwo points to be measured. Also, by setting a residual impedance whichdoes not affect the measurement of the impedance of the measuringobject, the impedance measurement can be performed with precision.

In measuring the output-terminal-side AC resistance RB of the matchingcircuit 2A, the conductive line 110 of the fixture is connected to thepoint PR, and the terminals 102 a to 102 h connected to the conductivewires 101 a to 101 h of the fixture are screwed to the matching box 2 ina substantially symmetrical manner about the point PR using screws 114,as in the above.

In the plasma processing units 75 to 77 in this embodiment, the input-and output-terminal-side AC resistances RA and RB in the matchingcircuit 2A for plasma excitation electrode 4 are adjusted while placingthe substrate 16 on the susceptor electrode 8. Alternatively, thesubstrate 16 may be placed on the plasma excitation electrode (cathode)4 in order to perform reactive ion etching (RIE).

Second Embodiment

A second embodiment of a plasma processing apparatus and an inspectionmethod therefor will now be explained with reference to the drawings.

FIG. 10 is a cross-sectional view showing an overall structure of aplasma processing apparatus 91 of the second embodiment. As shown inFIG. 10, the plasma processing apparatus 91 has a load-lock chamber 93,a heating unit 99, and plasma processing units 95 and 96 which areprovided around a substantially square transfer chamber (waitingchamber) 92. The transfer chamber 92 contains a transfer robot fortransferring substrates and has gates g1, g2, g3, and g4 at theinterfaces with the units. The transfer chamber 92, the heating unit 99,and the plasma processing units 95 and 96 are evacuated to a high vacuumby individual high-vacuum pumps. The load-lock chamber 93 is evacuatedto a low vacuum by a low-vacuum pump.

The components of the plasma processing apparatus 91 of this embodimentcorrespond to those of the plasma processing apparatus 71 of the firstembodiment shown in FIGS. 1 to 7. That is, the transfer chamber 92corresponds to the transfer chamber 72, the heating unit 99 correspondsto the annealing unit 79, and the load-lock chamber 93 corresponds tothe loading chamber 73 and the unloading chamber 74. The componentshaving the same configurations are not described.

The plasma processing units 95 and 96 correspond to the plasmaprocessing units 75 and 76 in the first embodiment shown in FIGS. 1 to5. The plasma processing units 95 and 96 have substantially the samestructure and may perform either different types of processes to depositdifferent types of layers or the same processes using the same processrecipe.

As shown in FIG. 10, the plasma processing units 95 and 96 are connectedto the impedance meter AN via switches SW2, etc., described below. Ineach of the plasma processing units 95 and 96, an input-terminal-side ACresistance RA of the matching circuit 2A is measured at theinput-terminal-side of the matching circuit 2A to calculate a variation<RA> defined by equation (14A) below:<RA>=(RA _(max) −RA _(min))/(RA _(max) +RA _(min))  (14A)wherein RA_(max) and RA_(min) are the maximum and minimum values of ACresistance RA between these units.

Also, in each of the plasma processing units 95 and 96, anoutput-terminal-side AC resistance RB of the matching circuit 2A ismeasured at the output-terminal-side of the matching circuit 2A tocalculate a variation <RB> defined by equation (14B) below:<RB>=(RB _(max) −RB _(min))/(RB _(max) +RB _(min))  (14B)wherein RB_(max) and RB_(min) are the maximum and minimum values of ACresistance RB between the plasma processing units 95 and 96. Each of thevariations <RA> and <RB> is set at a value within a predetermined range.

Now, the structure of the plasma processing unit will be described usingthe plasma processing unit 95 as an example.

FIG. 11 is a cross-sectional view showing an overall structure of theplasma processing unit 95 of this embodiment. FIG. 12 is across-sectional view showing the matching circuit 2A of FIG. 11, andFIG. 13 is a schematic circuit diagram for describing parasiticresistances in the matching circuit 2A of FIG. 12.

The plasma processing unit 95 is of a dual-frequency-excitation type anddiffers from the plasma processing unit 75 of the first embodiment shownin FIGS. 2 to 5 in that power is supplied to the susceptor electrode 8side. The configuration of the passive elements constituting thematching circuit 2A and the settings of the AC resistances RA and RB arealso different. Other corresponding components are represented by thesame reference numerals and the descriptions thereof are omitted.

In the plasma processing units 95 and 96, a variation <RA> defined byequation (14A):<RA>=(RA _(max) −RA _(min))/(RA _(max) +RA _(min))  (14A)wherein RA_(max) and RA_(min) are the maximum and minimum values,respectively, of AC resistance RA measured from the input-terminal-sideof the matching circuit 2A of each of plasma processing units 95 and 96is set at a value within a predetermined range.

A variation <RB> defined by equation (14B):<RB>=(RB _(max) −RB _(min))/(RB _(max) +RB _(min))  (14B)wherein RB_(max) and RB_(min) are the maximum and minimum values,respectively, of AC resistance RB measured at the output-terminal-sideof the matching circuit 2A of each of the plasma processing units 95 and96, is set at a value within the predetermined range.

As shown in FIGS. 11 and 12, the plasma processing unit 95 has asusceptor shield 12 provided under the susceptor electrode 8. Insulators12C composed of an electrically insulative material are provided arounda shaft 13 and between the susceptor electrode 8 and the susceptorshield 12 to electrically isolate the susceptor electrode 8 from thesusceptor shield 12. The insulators 12C also serve to maintain a highvacuum in the plasma processing chamber 60. The susceptor electrode 8and the susceptor shield 12 can be moved vertically by the bellows 11 toadjust the distance between the plasma excitation electrodes 4 and thesusceptor electrode 8. The susceptor electrode 8 is connected to asecond radiofrequency generator 27 via a feed plate 28 connected to thebottom end of the shaft 13 and a matching circuit 25 housed in asusceptor-electrode-side matching box 26.

The feed plate 28 is covered by a chassis 29 connected to the bottom endof a cylindrical support 12B of the susceptor shield 12. The chassis 29is connected to the matching box 26 by a shielding line of a feed line27A as a coaxial cable and is grounded along with the matching box 26.Thus, the susceptor shield 12, the chassis 29, and the matching box 26have the same DC potential.

The matching circuit 25 matches the impedances of the secondradiofrequency generator 27 and the susceptor electrode 8. Referring toFIGS. 11 and 12, the matching circuit 25 has, as passive elements, atuning coil 30 and a tuning capacitor 31 which are connected in seriesbetween the second radiofrequency generator 27 and the feed plate 28,and a load capacitor 32 connected in parallel with the tuning coil 30and the tuning capacitor 31. One end of the load capacitor 32 isconnected to the matching box 26. In short, the matching circuit 25 hassubstantially the same structure as that of the matching circuit 2A. Thematching box 26 and the end of the load capacitor 32 are set to a groundpotential through the shielding line of the feed line 27A.Alternatively, another tuning coil may be connected in series to thetuning coil 30, and another load capacitor may be connected in parallelto the load capacitor 32.

The feed plate 28 is identical to the feed plate 3. The input end of thefeed plate 28 is screwed to the matching circuit 25, and the output endis screwed to the shaft 13.

As shown in FIGS. 11 to 13, the matching circuit 2A is provided betweenthe radiofrequency generator 1 and the feed plate 3 and has, as passiveelements, an inductance coil 23, a tuning capacitor 24 comprising anair-variable capacitor, and a load capacitor 22 comprising avacuum-variable capacitor. The matching circuit 2A also includes acoaxial cable K1 and conductors R1 to R4 made of copper plates forconnecting these passive elements.

The conductor R1, the coaxial cable K1, the conductor R3, the inductancecoil 23, the conductor R4, and the tuning capacitor 24 are connected inseries from the input-terminal-side toward the output-terminal sidewhile the load capacitor 22 is connected to these elements in parallelat a branching point B1 located between the conductor R3 and theinductance coil 23. One end of the load capacitor 22 is connected to thematching box 2 (ground potential portion) at a connection point BP1through the conductor R2. The shielding line of the coaxial cable K1 isconnected to the matching box 2 (ground potential portion) via abranching point B2 at a connection point BP2.

Among passive elements constituting the matching circuit 2A, the tuningcapacitor 24 is located at the last stage, and the output terminal ofthe tuning capacitor 24 functions as the output terminal of the matchingcircuit 2A. The tuning capacitor 24 is connected to the plasmaexcitation electrode 4 through the feed plate 3.

In the plasma processing unit 95 of this embodiment, the substrate 16 tobe treated is placed on the susceptor electrode 8, radiofrequencyvoltage is applied to the plasma excitation electrode 4 from the firstradiofrequency generator 1 and to the susceptor electrode 8 from thesecond radiofrequency generator 27, while a reactive gas is fed into theplasma processing chamber 60 through the gas feeding tube 17 and theshower holes 7 to generate a plasma, and plasma processing such asdeposition or the like is performed on the substrate 16. During theprocess, radiofrequency power of approximately 13.56 MHz or more, forexample, a radiofrequency power of 13.56 MHz, 27.12 MHz, 40.68 MHz, orthe like, is supplied from the first radiofrequency generator 1. Thesecond radiofrequency generator 27 may supply either the sameradiofrequency power as does the first radiofrequency generator 1 or aradiofrequency power of a different frequency, e.g., 1.6 MHz.

The AC resistances RA and RB in the matching circuit 2A of the plasmaprocessing unit 95 of this embodiment are measured and defined as in thefirst embodiment. More specifically, the AC resistances RA and RB ofthis embodiment are measured and defined as shown in FIGS. 11 to 14.

The measured region of the matching circuit 2A in this embodiment is thesame as in the first embodiment. That is, the matching circuit 2A isdisconnected from the plasma processing unit at a point PR3corresponding to the input terminal of the passive element located atthe first stage of the matching circuit 2A and at a point PRcorresponding to the output terminal of the passive element located atthe last stage of the matching circuit 2A when the radiofrequencycharacteristics of the matching circuit 2A are measured. Moreparticularly, as shown in FIGS. 12 to 14, the feed line 1A connected tothe matching circuit 2A is disconnected from the matching circuit 2Awhile the feed plate 3 is disconnected from the matching circuit 2A atthe point PR by removing the screws connecting the output terminal ofthe matching circuit 2A to the feed plate 3.

As shown in FIG. 13, in measuring the input-terminal-side AC resistanceRA in the above measured region, the connection point BP2 is firstdetached from the matching box 2, and the probe 105 of the impedancemeter (radiofrequency measuring instrument) AN is connected to the pointPR3 and to a ground position (ground potential portion) of the matchingbox 2 as shown by broken lines in FIG. 13, as in the first embodiment.The frequency oscillated by the impedance meter AN is set at the samefrequency as a power frequency f_(e), i.e., about 40.68 MHz, to measurethe vector quantity (Z, θ) of the impedance in the above measured regionof the matching circuit 2A. The real part in the complex expression ofthe impedance is calculated therefrom and defined as aninput-terminal-side AC resistance RA_(BP1).

The radiofrequency elements contributing to the input-terminal-side ACresistance RA of the matching circuit 2A lying in the circuit indicatedby an arrow I_(RA) in FIG. 13 from the point PR3 to the connection pointBP1 via the branching point B1 are as follows:

Parasitic resistance R_(R1) in the conductor R1

Inductance L_(R1) in the conductor R1

Parasitic resistance R_(K1) in the coaxial cable K1

Inductance L_(K1) in the coaxial cable K1

Parasitic resistance R_(R3) in the conductor R3

Inductance L_(R3) in the conductor R3

Capacitance C_(L) of the load capacitor 22

Parasitic resistance R_(R2) in the conductor R2

Inductance L_(R2) in the conductor R2

Referring to FIG. 13, among the above-described radiofrequency elements,the parasitic resistance R_(R1) in the conductor R1, the parasiticresistance R_(K1) in the coaxial cable K1, the parasitic resistanceR_(R3) in the conductor R3, and the parasitic resistance R_(R2) in theconductor R2 are measured as the input-terminal-side AC resistanceRA_(BP1) of the matching circuit 2A.

In measuring the input-terminal-side AC resistance RA_(BP1), theparasitic resistance R_(R1) includes resistance of the coaxial cable K1up to the branching point B2, the parasitic resistance R_(R3) includesthe resistance from the branching point B1 to the load capacitor 22. Theparasitic resistances not illustrated in the circuit indicated by thearrow I_(RA) are also included in these resistances.

Next, as shown in FIG. 14, the connection point BP1 is disconnected fromthe matching box 2 and the connection point BP2 is connected to thematching box 2 to measure an input-terminal-side AC resistance RA_(BP2).As in the above, the probe 105 of the impedance meter is connected tothe point PR and to the ground position (ground potential portion) ofthe matching box 2, and the frequency oscillated by the impedance meterAN is set at-the same frequency as a power frequency f_(e), i.e., about40.68 MHz, to measure the vector quantity (Z, θ) of the impedance in theabove measured region of the matching circuit 2A. The real part in thecomplex expression of the impedance is calculated therefrom and definedas the input-terminal-side AC resistance RA_(BP2).

The radiofrequency elements contributing to the input-terminal-side ACresistance RA_(BP2) of the matching circuit 2A lying in the circuitindicated by an arrow I_(RA) in FIG. 14 from the point PR3 to theconnection point BP2 via the branching point B1 are as follows:

Parasitic resistance R_(R1) in the conductor R1

Inductance L_(R1) in the conductor R1

Parasitic resistance R_(K1) in the coaxial cable K1

Inductance L_(K1) in the coaxial cable K1

Capacitance C_(K1) in the coaxial cable K1

wherein the capacitance C_(K1) is the capacitance generated with theshielding line.

Referring to FIG. 14, among the above radiofrequency elements, theparasitic resistance R_(R1) in the conductor R1 and the parasiticresistance R_(K1) in the coaxial cable K1 are measured as theinput-terminal-side AC resistance RA_(BP2) of the matching circuit 2A.

In FIG. 14, the parasitic resistance R_(K1) in the coaxial cable K1 isillustrated in FIG. 14 as if it is positioned at the side closer to thepoint PR than is the branching point B2. In the actual measurement ofthe input-terminal-side AC resistance RA_(BP2), however, the parasiticresistance R_(K1) includes resistance of the coaxial cable K1,resistance existing at the connection point BP2 side, and parasiticresistance not illustrated in the circuit shown by the arrow I_(RA).

The output-terminal-side AC resistance RB of the matching circuit 2A ismeasured in a manner similar to the above description. As shown in FIG.13, while the connection point BP2 is detached from the matching box 2,the probe 105 of the impedance meter AN is attached to a ground position(ground voltage portion) of the matching box 2 and to the point PR3, asin the first embodiment. The frequency oscillated by the impedance meterAN is then set at the same frequency as the power frequency f_(e), i.e.,about 40.68 MHz, to measure the vector quantity (Z, θ) of the impedancein the matching circuit 2A. The real part of the complex expression ofthe impedance is calculated therefrom and defined as theoutput-terminal-side AC resistance RB_(BP1).

The radiofrequency elements contributing to the output-terminal-side ACresistance RB_(BPL) in FIG. 13 of the matching circuit 2A lying on thepath indicated by an arrow I_(RB) from the point PR to the connectionpoint BP1 to the matching box 2 which is a ground potential portion, viathe branching point B1 are as follows:

Capacitance C_(T) of the tuning capacitor 24

Parasitic resistance R_(R4) in the conductor R4

Inductance L_(R4) in the conductor R4

Parasitic resistance R_(LT) in the inductance coil 23

Inductance L_(LT) in the inductance coil 23

Capacitance C_(L) of the load capacitor 22

Parasitic resistance R_(R2) in the conductor R2

Inductance L_(R2) in the conductor R2

Among these radiofrequency elements, the parasitic resistance R_(R4) inthe conductor R4, the parasitic resistance R_(LT) in the inductance coil23, and the parasitic resistance R_(R2) in the conductor R2 are measuredas the output-terminal-side AC resistance RB_(BP1) in the matchingcircuit 2A.

In measuring the output-terminal-side AC resistance RB_(BP1), theparasitic resistance R_(LT) includes parasitic resistances notillustrated in the circuit indicated by the arrow I_(RB) such as theresistance from the branching point B1 to the load capacitor 22.

Next, referring to FIG. 14, in measuring the output-terminal-side ACresistance RB_(BP2), the connection point BP1 is detached from thematching box 2 while the connection point BP2 is connected to thematching box 2. The probe 105 of the impedance meter AN is connected tothe point PR and to the matching circuit 2A which is a ground potentialportion. The frequency oscillated from the impedance meter AN is thenset at a frequency the same as the power frequency f_(e) which is about40.68 MHz, for example, to measure the vector quantity (Z, θ) of theimpedance in the above measured region of the matching circuit 2A. Thereal part in the complex expression of the impedance is calculatedtherefrom and defined as the output-terminal-side AC resistanceRB_(BP2).

The radiofrequency elements contributing to the output-terminal-side ACresistance RB_(BP2) of the matching circuit 2A lying on the pathindicated by an arrow I_(RB) in FIG. 14 from the point PR to theconnection point BP2 on the matching box 2 which is a ground potentialportion, via the branching point B2 are as follows:

Capacitance C_(T) of the tuning capacitor 24

Parasitic resistance R_(R4) in the conductor R4

Inductance L_(R4) in the conductor R4

Parasitic resistance R_(LT) in the inductance coil 23

Inductance L_(T) in the inductance coil 23

Parasitic resistance R_(R3) in the conductor R3

Inductance L_(R3) in the conductor R3

Parasitic resistance R_(K1) in the coaxial cable K1

Inductance L_(K1) in the coaxial cable K1

Capacitance C_(K1) in the coaxial cable K1.

Among these radiofrequency elements, the parasitic resistance R_(R4) inthe conductor R4, the parasitic resistance R_(LT) in the inductance coil23, the parasitic resistance R_(R3) in the conductor R3, and theparasitic resistance R_(K1) in the coaxial cable K1 are measured as theoutput-terminal-side AC resistance RB_(BP2), as shown in FIG. 14.

The input- and output-terminal-side AC resistances RA and RB in thematching circuit 2A of the plasma processing unit 95 are set within apredetermined range suitable for the operation of the plasma processingunit 95. In particular, the input-terminal-side AC resistance RA_(BP1),the input-terminal-side AC resistance RA_(BP2), the output-terminal-sideAC resistance RB_(BP1), and the output-terminal-side AC resistanceRB_(BP2) are each set at a value within a predetermined range describedbelow.

Examples of a method for optimizing the AC resistances RA and RB are

(1) Adjusting the shape, i.e., the length and the width, of the copperplates constituting the conductors R1 to R4.

(2) Adjusting the state of assembly of the copper plates constitutingthe conductors R1 to R4.

(3) Adjusting the shape, i.e., the length and the width, of the coaxialcable K1.

(4) Plating the copper plates constituting the conductors R1 to R4 withsilver.

In the plasma processing apparatus 91 of this embodiment, the plasmaprocessing units 95 and 96 have substantially the same structure. The ACresistances. RA and RB, more specifically, the AC resistances RA_(BP1),RA_(BP2), RB_(BP1), and RB_(BP2), of the plasma processing unit 96 areset in the same manner as in the plasma processing unit 95.

The power frequency f_(e) in the plasma processing units 95 and 96 isset at 40.68 MHz to measure the AC resistances RA and RB.

The AC resistances RA and RB are radiofrequency characteristics mainlydetermined by the mechanical structure and are considered to varybetween different units.

Regarding the input-terminal-side AC resistance RA, a variation<RA_(BP1)> in the input-terminal-side AC resistance RA_(BP1) of theplasma processing units 95 and 96 is defined by equation (14A′) below:<RA _(BP1)>=(RA _(BP1-max) −RA _(BP1-min))/(RA _(BP1-max) +RA_(BP1 -min))  (14A′)wherein RA_(BP1-max) and RA_(BP1-min) are the maximum and minimumvalues, respectively, between an input-terminal-side AC resistanceRA_(BP1-95) of the plasma processing unit 95 and an input-terminal-sideAC resistance RA_(BP1-96) of the plasma processing unit 96.

Similarly, a variation <RA_(BP2)> in the input-terminal-side ACresistance RA_(BP2) of the plasma processing units 95 and 96 is definedby equation (14A″) below:<RA_(BP2)>=(RA _(BP2-max) −RA _(BP2-min))/(RA _(BP2-max) +RA_(BP2-min))  (14A″)wherein RA_(BP2-max) and RA_(BP2-min) are the maximum and minimumvalues, respectively, between an input-terminal-side AC resistanceRA_(BP2-95) of the plasma processing unit 95 and an input-terminal-sideAC resistance RA_(BP2-96) of the plasma processing unit 96.

Then, the variation <RA_(BP1)> in the input-terminal-side AC resistanceRA_(BP1) and the variation <RA_(BP2)> in the input-terminal-side ACresistance RA_(BP2) are compared and the larger one of the two isdefined as a variation <RA> of the input-terminal-side AC resistance RA.The values of the variations expressed by equations (14A′) and (14A″)are then each set at a value less than 0.4. In short, both variations<RA_(BP1)> and <RA_(BP2)> corresponding to the connection point BP1 andBP2, respectively, are set at a value within a predetermined range,i.e., less than 0.4.

The variation <RA> of the input-terminal-side AC resistance RA can beadjusted by the methods (1) to (4) described above.

Regarding the output-terminal-side AC resistance RB, a variation<RB_(BP1)> in the output-terminal-side AC resistance RB_(BP1) betweenthe plasma processing units 95 and 96 is defined by equation 14B′ below:<RB _(BP1)>=(RB _(BP1-max) −RB _(BP1-min))/(RB _(BP1-max) +RB_(BP1-min))  (14B′)wherein RB_(BP1-max) and RB_(BP1-min) are the maximum and minimumvalues, respectively, between an output-terminal-side AC resistanceRB_(BP1-95) of the plasma processing unit 95 and an output-terminal-sideAC resistance RB_(BP1-96) of the plasma processing unit 96.

Similarly, a variation <RB_(BP2)>in the output-terminal-side ACresistances RB_(BP2) of the plasma processing units 95 and 96 is definedas equation 14B″ below:<RB _(BP2)>=(RB _(BP2-max) −RB _(BP2-min))/(RB _(BP2-max) +RB_(BP2-min))  (14B″)wherein RB_(BP2-max) and RB_(BP2-min) are the maximum and minimum valuesbetween an output-terminal-side AC resistance RB_(BP2-95) of the plasmaprocessing unit 95 and an output-terminal-side AC resistance RB_(BP2-96)of the plasma processing unit 96.

Then, the variation <RB_(BP1)> in the output-terminal-side AC resistanceRB_(BP1) and the variation <RB_(BP2)> in the output-terminal-side ACresistance RB_(BP2) are compared and the larger one of two is defined asthe variation <RB>of the output-terminal-side AC resistance RB. Thevalues of the variations expressed by equations (14B′) and (14B″) arethen set at a value less than 0.4 each. In short, both variations<RB_(BP1)> and <RB_(BP2)> corresponding to the connection point BP1 andBP2, respectively, are set at a value within a predetermined range,i.e., less than 0.4.

The variation <RB> in the output-terminal-side AC resistance RB can beadjusted by the methods (1) to (4) described above.

In the plasma processing apparatus 91, a gate g0 is opened to transferthe substrate 16 into the load-lock chamber 93. The gate g0 is closed toevacuate the load-lock chamber 93 with a low-vacuum pump. The gates g1and g2 are opened to transfer the substrate 16 from the load-lockchamber 93 to the heating unit 99 by a transfer arm of a transfer robotin the transfer chamber 92. The gates g1 and g2 are closed to evacuatethe transfer chamber 92 and the heating unit 99 using a high-vacuumpump. After the substrate 16 is annealed, the gates g2 and g4 are openedto transfer the annealed substrate 16 to the plasma processing unit 95with the transfer arm of the transfer robot. After the substrate 16 isprocessed in the plasma processing unit 95, the gates g3 and g4 areopened to transfer the substrate 16 to the plasma processing unit 96 bythe transfer arm of the transfer robot in the transfer chamber 92. Afterthe substrate 16 is processed in the plasma processing unit 96, thegates g1 and g3 are opened to transfer the substrate 16 to the load-lockchamber 93 with the transfer arm of the transfer robot in the transferchamber 92.

Individual sections are automatically operated by a controller section,although the processing conditions such as layer deposition conditionsin these processing chambers and the processing sequence are set by anoperator. In using this plasma processing apparatus 91, an untreatedsubstrate 16 is placed in a loading cassette in the load-lock chamber 93and the operator pushes a start switch. The substrate 16 is sequentiallytransferred from the loading cassette to the processing units by thetransfer robot. After a series of processing steps are performed inthese processing chambers, the substrate 16 is placed in the unloading(loading) cassette by the transfer robot.

In these plasma processing units 95 and 96, the substrate 16 is placedon the susceptor electrode 8, as in the first embodiment. Theradiofrequency generator 1 applies a radiofrequency voltage to theplasma excitation electrode 4, and the second radiofrequency generator27 applies a radiofrequency voltage to the susceptor electrode 8 while areactive gas is fed into the plasma processing chamber 60 from the gasfeeding tube 17 via the holes 7 in the shower plate 6 to generate aplasma for forming an amorphous silicon layer, a silicon oxide layer, ora silicon nitride layer on the substrate 16.

The plasma processing apparatus 91 and the inspection therefor accordingto this embodiment achieve the same advantages as in the firstembodiment. Moreover, the variations in the input- andoutput-terminal-side AC resistances RA and RB of the matching circuits2A of the plasma processing units 95 and 96 are adjusted to be less than0.4. Thus, the difference in the radiofrequency characteristics betweenthe plasma processing units 95 and 96 can be minimized, the state of theplasma processing units 95 and 96 can be maintained within apredetermined range indicated by the impedance characteristics, and theeffective power consumed in the plasma spaces of the plasma processingunits 95 and 96 can be made substantially the same.

As a result, substantially the same plasma process results can beachieved by applying the same process recipe to the plasma processingunits 95 and 96. That is, when applied to a deposition process,substantially uniform layer characteristics, such as layer thickness,isolation voltage, and etching rate can be achieved. More specifically,the variation in the thickness of the layers deposited using the sameprocess recipe can be maintained within ±3% by setting the variation toa value less than 0.4.

When a plurality of connection points BP1 and BP2 are provided as inthis embodiment, an input-terminal-side AC resistance RA_(BP1) and anoutput-terminal-side AC resistance RB_(BP1) are measured while theconnection point BP1 is connected to the matching box 2 and theconnection point BP2 is disconnected from the matching box 2. Aninput-terminal-side AC resistance RA_(BP2) and an output-terminal-sideAC resistance RB_(BP2) are measured while switching the connectionpoint, i.e., while the connection point BP1 is disconnected from thematching box 2 and the connection point BP2 is connected to the matchingbox 2. In short, the state of connection is altered for each of theconnection points BP1 and BP2 to define the different measured regions,and the input-terminal-side AC resistance RA_(BP1), input-terminal-sideAC resistance RA_(BP2), output-terminal-side AC resistance RB_(BP1), andoutput-terminal-side AC resistance RB_(BP2) of the plasma processingunits 95 and 96 are individually measured for each of these measuredregions. The variations <RA> and <RB> in the AC resistance defined byequations (14A′), (14A″), (14B′), and (14B″) are then optimized. Thus,substantially the same effective power is consumed in the plasma spacesof the plasma processing units 95 and 96.

According to the plasma processing apparatus 91 and the inspectionmethod therefor of this embodiment, both the input-terminal-side ACresistances RA and the output-terminal-side AC resistances RB of thematching circuits 2A of the plasma processing units 95 and 96 areadjusted. Thus, the parasitic resistances in the matching circuit 2Ahaving a plurality of branching points B1 and B2 can be adjusted and thedifference between the units can be minimized. Accordingly, theimpedance characteristics of the plasma processing units 95 and 96 canbe efficiently measured.

Although the input- and output-terminal-side AC resistances RA and RBare set in relation to the plasma excitation electrode 4 in thisembodiment, the input- and output-terminal-side AC resistances RA and RBmay be set in relation to the matching circuit 25 at the susceptorelectrode 8 side. In such a case, the output-terminal-side AC resistanceRB in the matching circuit 25 is measured at a point PR′, and theinput-terminal-side AC resistance RA of the matching circuit 25 ismeasured at a point PR3′, as shown in FIGS. 11 and 12.

Moreover, the present embodiment can be applied to an inductive coupledplasma (ICP) excitation type plasma processing apparatus, a radial lineslot antenna (RLSA) type plasma processing apparatus, and a reactive ionetching (RIE) type processing apparatus, instead of the parallel platetype plasma processing apparatus.

A target material may be installed instead of the electrodes 4 and 8 toperform a sputtering process as a plasma treatment.

Third Embodiment

A third embodiment of a plasma processing apparatus and an inspectionmethod therefor will be explained below with reference to the drawings.

FIG. 15 is a schematic diagram showing an overall structure of a plasmaprocessing unit of this embodiment.

The structure of the plasma processing apparatus of this embodiment hassubstantially the same structure as that of the first embodiment andsecond embodiment. The plasma processing apparatus of this embodimentdiffers from the first and the second embodiment in the structure of theplasma processing unit, and more specifically, the configuration of thematching circuit 2A and switches. Like components are represented by thesame reference numerals and the explanations thereof are omitted.

The plasma processing units 75, 76, 77, 95 and 96 of this embodiment areof a dual-frequency excitation type as in the second embodiment.Referring to FIG. 15, in each of the plasma processing units 75, 76, 77,95 and 96, the input-terminal-side AC resistance RA as a radiofrequencycharacteristic is measured at a point PR2 which corresponds to the inputterminal of the radiofrequency supplier (feed line) 1A connected to theradiofrequency generator 1.

FIG. 16 is a schematic diagram showing an overall structure of thematching circuit 2A in FIG. 15. FIG. 17 is a schematic circuit diagramfor describing parasitic resistances in the matching circuit 2A of FIG.16.

Referring to FIGS. 15 to 17, the matching circuit 2A is provided betweenthe radiofrequency generator 1 and the feed plate 3 and has, as passiveelements, the tuning capacitor 24 comprising the air-variable capacitorand the load capacitor 22 comprising the vacuum-variable capacitor. Thematching circuit 2A also includes the conductors R1 to R4, and aconductor R5 for connecting these passive elements. The conductors R1 toR5 are each made of a copper plate.

The conductors R1, R5, R3, and R4, and the tuning capacitor 24 areconnected in series from the input-terminal-side toward theoutput-terminal-side of the matching circuit 2A. The load capacitor 22is connected in parallel to these elements at the branching point B1located between the conductors R3 and R4. One end of the load capacitor22 is connected to the matching box 2 (ground potential portion) throughthe conductor R2 at the connection point BP1.

The tuning capacitor 24 is located at the last stage in the matchingcircuit 2A among the passive elements constituting the matching circuit2A. The output terminal of the tuning capacitor 24 thus functions as theoutput terminal of the matching circuit 2A, and the tuning capacitor 24is connected to the plasma excitation electrode 4 through the feed plate3.

Referring to FIGS. 15 to 17, connected to the point PR3 are a measuringterminal 61 for measuring the input-terminal-side AC resistance RA, aconnecting line 61A which is a coaxial cable for connecting themeasuring terminal 61 to the impedance meter AN, and a switch SW5 forswitching the connection between the feed line 1A and the impedancemeter AN during the measurement of the radiofrequency characteristicsand during plasma generation. The point PR3 is connected to the switchSW5 through the measuring terminal 61. The feed line 1A and theconnecting line 61A are also connected to the switch SW5. The groundpotential for the switch SW5, the feed line 1A, and the connecting line61A is the matching box 2 during both plasma generation andradiofrequency characteristic measurement.

The impedance between the point PR3 and the point PR2 and the impedancebetween the point PR3 and the impedance meter AN via the connecting line61A are set to be equal to each other. More particularly, the length ofthe feed line 1A and the length of the connecting line 61A are set to beequal to each other. Moreover, the impedances between the impedancemeter AN and each of the plasma processing units 75, 76, 77, 95, and 96are set to be equal to one another. In this embodiment, the measurementof the radiofrequency characteristics, such as impedance andparticularly the input-terminal-side AC resistance RA, can be conductedby operating the switch SW5 without having to detach/attach the matchingcircuit 2A from/to the impedance meter AN.

Referring to FIGS. 15 to 17, a measuring terminal 61′ for measuring theoutput-terminal-side AC resistance RB, a connecting line 61B which is acoaxial cable for connecting the measuring terminal 61′ to the impedancemeter AN, and switches SW1 and SW1′ are provided in the vicinity of thepoint PR. The switches SW1 and SW1′ connects the matching circuit 2A tothe impedance meter AN during the radiofrequency measurement andconnects the matching circuit 2A to the feed plate 3 during the plasmageneration. The point PR, the measuring terminal 61′, and an output lineextending to the feed plate 3 are connected to the switch SW1. Theswitch SW1′ is connected to the matching box 2 and to the groundpotential portion for the impedance meter AN via the shielding line ofthe connecting line 61B. The ground potential of the switches SW1 andSW1′ and the connecting line 61B is the matching box 2 during bothplasma generation and radiofrequency characteristics measurement.

The connecting lines 61B for the plasma processing units 75, 76, 77, 95,and 96 are set to have the same length so that the impedances betweenthe impedance meter AN and each of the plasma processing units are setto be equal to one another. In this manner, the measurement of theradiofrequency characteristics, such as impedance and particularly theoutput-terminal-side AC resistance RB, can be conducted simply byoperating the switches SW1 and SW1′ without having to detach/attach thematching circuit 2A from/to the impedance meter AN.

In each of the plasma processing units 75, 76, 77, 95, and 96 of thisembodiment, the AC resistances RA and RB as radiofrequencycharacteristics in the matching circuits 2A are measured and defined asin the first and second embodiments.

Referring to FIG. 17, in measuring the input-terminal-side AC resistanceRA, the switches SW1 and SW1′ are operated to disconnect the matchingcircuit 2A from the plasma processing unit at the point PR. Meanwhile,the switch SW5 is operated to connect the matching circuit 2A to theimpedance meter AN, the frequency oscillated by the impedance meter ANis set to about 40.68 MHz which is equal to a power frequency f_(e), forexample, and the vector quantity (Z, θ) of the impedance in the abovemeasured region of the matching circuit 2A is measured to calculate thereal part in the complex expression of the impedance which is defined asthe AC resistance.

The radiofrequency elements contributing to the input-terminal-side ACresistance RA in the matching circuit 2A lying on the path indicated byan arrow I_(RA) in FIG. 17 extending from a point (PR2), which isequivalent to the point PR2 located at the radiofrequency generator 1side, to the ground potential portion such as the matching box 2 via thebranching points B3 and B1 are as follows:

Parasitic resistance R_(61A) in the connecting line 61A

Inductance L_(61A) in the connecting line 61A

Capacitance C_(61A) in the connecting line 61A

Parasitic resistance R_(SW5) in the switch SW5

Inductance L_(SW5) in the switch SW5

Parasitic resistance R₆₁ in the measuring terminal 61

Inductance L₆₁ in the measuring terminal 61

Parasitic resistance R_(R1) in the conductor R1

Inductance L_(R1) in the conductor R1

Parasitic resistance R_(R5) in the conductor R5

Inductance L_(R5) in the conductor R5

Parasitic resistance R_(R3) in the conductor R3

Inductance L_(R3) in the conductor R3

Capacitance C_(L) of the load capacitor 22

Parasitic resistance R_(R2) in the conductor R2

Inductance L_(R2) in the conductor R2

wherein the capacitance C_(61A) of the connecting line 61A is thecapacitance generated with the shielding line.

Among these radiofrequency elements, the parasitic resistance R_(61A) inthe connecting line 61A, the parasitic resistance R_(SW5) in the switchSW5, the parasitic resistance R₆₁ in the measuring terminal 61, theparasitic resistance R_(R1) in the conductor R1, the parasiticresistance R_(R5) in the conductor R5, the parasitic resistance R_(R3)in the conductor R3, and the parasitic resistance R_(R2) in theconductor R2 are measured as the input-terminal-side AC resistance RA inthe matching circuit 2A, as shown in FIG. 17.

In measuring the input-terminal-side AC resistance RA, the parasiticresistance R_(R3) includes resistances from the branching point B1 tothe load capacitor 22, i.e., parasitic resistances on the circuit I_(RA)not illustrated in the drawing.

Similarly, in measuring the output-terminal-side AC resistance RB, theswitch SW5 is operated to disconnect the matching circuit 2A from theradiofrequency generator 1 at the point PR3, and the switches SW1 andSW1′ are operated to connect the point PR of the matching circuit 2A tothe impedance meter AN. Meanwhile, the matching box 2 is connected tothe grounded portion of the impedance meter AN, the frequency oscillatedby the impedance meter AN is set to about 40.68 MHz which is the same asthe power frequency f_(e), for example, and the vector quantity (Z, θ)of the impedance in the above measured region of the matching circuit 2Ais measured. The real part in the complex expression of impedance iscalculated therefrom and is defined as the AC resistance.

The radiofrequency elements contributing to the output-terminal-side ACresistance RB in the matching circuit 2A lying on the path indicated byan arrow I_(RB) in FIG. 17 extending from the point PR to the connectionpoint BP1 as the ground potential portion via the branching point B1 areas follows:

Parasitic resistance R_(SW1) in the switch SW1

Inductance L_(SW1) in the switch SW1

Capacitance C_(T) of the tuning capacitor 24

Parasitic resistance R_(R4) in the conductor R4

Inductance L_(R4) in the conductor R4

Capacitance C_(L) of the load capacitor 22

Parasitic resistance R_(R2) in the conductor R2

Inductance L_(R2) in the conductor R2

Among these radiofrequency elements, the parasitic resistance R_(SW1) inthe switch SW1, the parasitic resistance R_(R4) in the conductor R4, andthe parasitic resistance R_(R2) in the conductor R2 are measured as theoutput-terminal-side AC resistance RB in the matching circuit 2A, asshown in FIG. 17.

In measuring the output-terminal-side AC resistance RB, the parasiticresistance R_(R4) includes parasitic resistances on the circuitindicated by the arrow I_(RB) not illustrated in the drawing, such asresistance from the branching point B1 to the load capacitor 22.

The following radiofrequency elements contribute to theoutput-terminal-side AC resistance RB in the matching circuit 2A duringmeasurement as shown in FIG. 17, but are negligible when radiofrequencypower is supplied to the plasma processing chamber from theradiofrequency generator 1.

Parasitic resistance R_(61B) in the connecting line 61B

Inductance L_(61B) in the connecting line 61B

Capacitance C_(61B) in the connecting line 61B

Parasitic resistance R_(61′) in the measuring terminal 61′

Inductance L_(61′) in the measuring terminal 61′

An operation is performed to eliminate the contribution from theseelements subsequent to the measurement of the output-terminal-side ACresistance RB.

In the matching circuit 2A of the plasma processing unit of thisembodiment, the input and output-terminal-side AC resistances RA and RBare maintained to a value within a range suitable for the operation ofthe plasma processing unit and variations among different plasmaprocessing units defined by equations (14A) and (14B) are adjusted as inthe first and second embodiments.

The plasma processing apparatus and the inspection method therefor ofthis embodiment achieve the same advantages as in the first and secondembodiments. Moreover, because the feed line 1A is included in themeasured region of the matching circuit 2A, the adjustment can beconducted including the parasitic resistances in the component whichsupplies electric power. Thus, compared to other embodiments notincluding the radiofrequency supplier (feed line) 1A in the measuredregion, the difference in radiofrequency characteristics of the matchingcircuits 2A and the feed lines 1A among a plurality of plasma processingunits can be further reduced. The effective power consumed in the plasmaspaces of the different plasma processing units can be madesubstantially the same, and the uniformity in the plasma process resultsusing the same process recipe can be further improved compared to thecase not including the feed line 1A in the measured region.

In the plasma processing apparatus and the inspection method therefor ofthis embodiment, the measuring terminals 61 and 61′ and the switchesSW5, SW1, and SW1′ are provided, and the impedance from the point PR3 tothe point PR2 is set to be equal to the impedance from the point PR3 tothe impedance meter AN via the connecting line 61A. Thus, radiofrequencycharacteristics, namely the input-terminal-side AC resistance RA and theoutput-terminal-side AC resistance RB, of each plasma processing unitcan be measured without having to detach/attach the matching circuit 2Afrom/to the radiofrequency generator 1 and the feed plate 3 and withouthaving to detach/attach the probe 105 for impedance measuring. By simplyoperating the switches SW5, SW1, and SW1′, the plasma processingapparatus in operating state can be switched to a state suitable formeasurement.

Moreover, in this embodiment, the lengths of the connecting lines 61A ofthe plasma processing units 75, 76, 77, 95 and 96 are set to be equal toeach other so that the impedances between the impedance meter AN andeach of the plasma processing units 75, 76, 77, 95, and 96 are the same.Thus, by simply operating the switch SW5, the input-terminal-side ACresistances RA as the radiofrequency characteristics of the plurality ofplasma processing units can be sequentially and efficiently measured.

Furthermore, since the connecting lines 61B of these plasma processingunits have the same length, the impedances between the impedance meterAN and each of plasma processing units are equal to one another. Thus,the output-terminal-side AC resistances RB of the plurality of plasmaprocessing units can be sequentially and efficiently measured byoperating the switches SW1 and SW1′.

Fourth Embodiment

A plasma processing apparatus and an inspection method thereforaccording to a fourth embodiment of the present invention will now beexplained with reference to the drawings.

FIG. 18 is a schematic diagram showing an overall structure of thematching circuit 2A of a plasma processing unit of this embodiment.

The structure of the plasma processing apparatus of this embodiment issubstantially the same as that according to the first to thirdembodiments shown in FIGS. 1 to 17. The plasma processing apparatus ofthis embodiment differs from that of the first to third embodiments inthe configuration of the matching circuit 2A in the plasma processingunit and the measured region of the matching circuit 2A. Like componentsare represented by the same reference numerals and the explanationsthereof are omitted.

Referring to FIG. 18, in each of the plasma processing units 75, 76, 77,95, and 96, the input-terminal-side AC resistance RA is measured at thepoint PR2 and the output-terminal-side AC resistance RB is measured atthe point PR4 which is located at the electrode-4-side and correspondsto the output terminal of the radiofrequency feeder (feed plate) 3connected to the matching circuit 2A, as in the third embodiment.

As in the first and second embodiment, the input terminal of thematching circuit 2A is directly connected to the feed line 1A withoutthe switch SW5 therebetween.

FIG. 19 is a schematic circuit diagram for describing parasiticresistances in the matching circuit 2A of FIG. 18.

The matching circuit 2A is, as shown in FIGS. 18 and 19, disposedbetween the radiofrequency generator 1 and the feed plate 3 and has, aspassive elements, inductance coil 23, the tuning capacitor 24 comprisingthe air-variable capacitor, and load capacitors 22A and 22B eachcomprising a vacuum-variable capacitor. The matching circuit 2A alsoincludes the conductors R1, R2, and R5 and a conductor R6 for connectingthese passive elements. Each of the conductors R1, R2, R5, and R6 ismade of a copper plate. The conductors R1 and R5, the inductance coil23, and the tuning capacitor 24 are connected in series from theinput-terminal-side of the matching circuit 2A to theoutput-terminal-side of the same. The load capacitor 22A is connected tothese elements in parallel at a branching point B4 disposed between theconductors R1 and R5, and the load capacitor 22B is also connected tothese elements in parallel at the branching point B1 disposed betweenthe conductor R5 and the inductance coil 23. One end of the loadcapacitor 22A is connected to the matching box 2 (ground potentialportion) at a connection point BP4 via the conductor R6. One end of theload capacitor 22B is connected to the matching box 2 (ground potentialportion) at the connection point BP1 via the conductor R2.

The tuning capacitor 24 is located at the last stage of the matchingcircuit 2A among the passive elements constituting the matching circuit2A. The output terminal of the tuning capacitor 24 functions as theoutput terminal of the matching circuit 2A. The tuning capacitor 24 isconnected to the plasma excitation electrode 4 via the feed plate 3.

The AC resistances RA and RB as the radiofrequency characteristics inthe matching circuit 2A of each of the plasma processing units 75, 76,77, 95, and 96 are measured and defined as in the first to thirdembodiments. Specifically, the AC resistances RA and RB are measured anddefined as shown in FIGS. 18 to 20 in this embodiment.

In order to define the measured region of the matching circuit 2A ofthis embodiment, the matching circuit 2A is separated from the plasmaprocessing unit at the point PR4 which corresponds to the outputterminal of the radiofrequency feeder (feed plate) 3, as shown in FIG.18. In other words, the matching circuit 2A and the feed plate 3connected to the matching circuit 2A are separated from the plasmaprocessing chamber 60. Meanwhile, the matching circuit 2A and the feedline 1A connected to the input terminal of the matching circuit 2A areseparated from the radiofrequency generator 1.

In this embodiment, the input-terminal-side AC resistance RA in theabove-described measured region is measured at the point PR2, as shownin FIG. 18.

Referring to FIG. 19, in measuring the input-terminal-side AC resistanceRA, the connection point BP4 is first detached from the matching box 2,and the probe 105 of the impedance meter AN is connected to a groundposition of the matching box 2 (ground potential portion) and to thepoint PR2, as in the first and second embodiments. The shielding line ofthe feed line 1A is grounded. The frequency oscillated by the impedancemeter AN is then set at about 40.68 MHz which is equal to the powerfrequency f_(e), for example, to measure the vector quantity (Z, θ) ofthe impedance in the above measured region of the matching circuit 2A.The real part in the complex expression of the impedance is calculatedtherefrom and is defined as the input-terminal-side AC resistanceRA_(BP1).

The radiofrequency elements contributing to the input-terminal-side ACresistance RA_(BP1) of the matching circuit 2A lying in the circuitindicated by an arrow I_(RA) in FIG. 19 extending from the point PR2 tothe connection point BP1 on the matching box 2 which is a groundpotential portion via the branching point B1 are as follows:

Parasitic resistance R_(1A) in the feed line 1A

Inductance L_(1A) in the feed line 1A

Capacitance C_(1A) of the feed line 1A

Parasitic resistance R_(RR1) in the conductor R1

Inductance L_(R1) in the conductor R1

Parasitic resistance R_(R5) in the conductor R5

Inductance L_(R5) in the conductor R5

Capacitance C_(LB) of the load capacitor 22B

Parasitic resistance R_(R2) in the conductor R2

Inductance L_(R2) in the conductor R2

wherein the capacitance C_(1A) of the feed line 1A is the capacitancegenerated with the shielding line.

Among these radiofrequency elements, the parasitic resistance R_(1A) inthe feed line 1A, the parasitic resistance R_(R1) in the conductor R1,the parasitic resistance R_(R5) in the conductor R5, and the parasiticresistance R_(R2) in the conductor R2 are measured as theinput-terminal-side AC resistance RA_(BP1) of the matching circuit 2A,as shown in FIG. 19.

Next, as shown in FIG. 20, the connection point BP1 is disconnected fromthe matching box 2 while connecting the connection point BP4 to thematching box 2 to measure the input-terminal-side AC resistanceRA_(BP2). As in the above, the probe 105 of the impedance meter AN isconnected to the point PR2 and to a ground position on the matching box2 (ground potential portion), and the frequency oscillated by theimpedance meter AN is set at the same frequency as a power frequencyf_(e), i.e., about 40.68 MHz, for example, to measure the vectorquantity (Z, θ) of the impedance in the above measured region of thematching circuit 2A. The real part of the complex expression of theimpedance is calculated therefrom and defined as the input-terminal-sideAC resistance RA_(BP2).

The radiofrequency elements contributing to the input-terminal-side ACresistance RA_(BP2) of the matching circuit 2A lying in the circuitindicated by the arrow I_(RA) in FIG. 20 extending from the point PR3 tothe connection point BP4 via the branching point B4 are as follows:

Parasitic resistance R_(1A) in the feed line 1A

Inductance L_(1A) in the feed line 1A

Capacitance C_(1A) in the feed line 1A

Parasitic resistance R_(R1) in the conductor R1

Inductance L_(R1) in the conductor R1

Capacitance C_(LA) in the load capacitor 22A

Parasitic resistance R_(R6) in the conductor R6

Inductance L_(R6) in the conductor R6

Among these radiofrequency elements, the parasitic resistance R_(1A) inthe feed line 1A, the parasitic resistance R_(R1) in the conductor R1,and the parasitic resistance R_(R6) in the conductor R6 are measured asthe input-terminal-side AC resistance RA_(BP2) of the matching circuit2A, as shown in FIG. 20.

In measuring the output-terminal-side AC resistance RB of the matchingcircuit 2A, the connection point BP4 is first detached from the matchingbox 2 and then the output-terminal-side AC resistance RB is measured atthe point PR4, as shown in FIG. 19. The probe 105 of the impedance meterAN is attached to the point PR4 and to a ground position on the matchingbox 2 (ground potential portion). The frequency oscillated by theimpedance meter AN is then set at the same frequency as the powerfrequency f_(e), i.e., about 40.68 MHz, for example, to measure thevector quantity (Z, θ) of the impedance in the above measured region ofthe matching circuit 2A. The real part of the complex expression of theimpedance is calculated therefrom and defined as theoutput-terminal-side AC resistance RB_(BP1).

Referring to FIG. 19, the radiofrequency elements contributing to theoutput-terminal-side AC resistance RB_(BP1) of the matching circuit 2Alying on the path indicated by an arrow I_(RB) extending from the pointPR4 to the connection point BP1 on the matching box 2 which is a groundpotential portion, via the branching point B1 are as follows:

Parasitic resistance R₃ in the feed plate 3

Inductance L₃ in the feed plate 3

Capacitance C_(T) of the tuning capacitor 24

Parasitic resistance R_(LT) in the inductance coil 23

Inductance L_(T) in the inductance coil 23

Capacitance C_(LB) of the load capacitor 22B

Parasitic resistance R_(R2) in the conductor R2

Inductance L_(R2) in the conductor R2

Among these radiofrequency elements, the parasitic resistance R_(R4) inthe conductor R4, the parasitic resistance R_(LT) in the inductance coil23, and the parasitic resistance R_(R2) in the conductor R2 are measuredas the output-terminal-side AC resistance RB_(BP1) in the matchingcircuit 2A, as shown in FIG. 19

Next, referring to FIG. 20, in measuring the output-terminal-side ACresistance RB_(BP2), the connection point BP1 is detached from thematching box 2 and the connection point BP4 is connected to the matchingbox 2. The probe 105 of the impedance meter AN is connected to the pointPR4 and to a ground position on the matching box 2 (ground potentialportion). The frequency oscillated from the impedance meter AN is thenset at a frequency same as the power frequency f_(e), i.e., about 40.68MHz, for example, to measure the vector quantity (Z, θ) of the impedancein the above measured region of the matching circuit 2A. The real partin the complex expression of the impedance is calculated therefrom anddefined as the output-terminal-side AC resistance RB_(BP2).

The radiofrequency elements contributing to the output-terminal-side ACresistance RB_(BP2) of the matching circuit 2A lying on the pathindicated by an arrow I_(RB) in FIG. 20 extending from the point PR4 tothe connection point BP4 on the matching box 2 which is a groundpotential portion, via the branching point B1 are as follows:

Parasitic resistance R₃ in the feed plate 3

Inductance L₃ in the feed plate 3

Capacitance C_(T) of the tuning capacitor 24

Parasitic resistance R_(LT) in the inductance coil 23

Inductance L_(T) in the inductance coil 23

Parasitic resistance R_(R5) in the conductor R5

Inductance L_(R5) in the conductor R5

Capacitance C_(LA) of the load capacitor 22A

Parasitic resistance R_(R6) in the conductor R6

Inductance L_(R6) in the conductor R6

Among these radiofrequency elements, the parasitic resistance R₃ in thefeed plate 3, the parasitic resistance R_(LT) in the inductance coil 23,the parasitic resistance R_(R5) in the conductor R5, and the parasiticresistance R_(R6) in the conductor R6 are measured as theoutput-terminal-side AC resistance RB_(BP2), as shown in FIG. 20.

In the matching circuit 2A of the plasma processing unit of thisembodiment, the AC resistances RA and RB as the radiofrequencycharacteristics are set to a value suitable for the operation of theplasma processing unit, as in the second embodiment. More specifically,the input-terminal-side AC resistance RA_(BP1), the input-terminal-sideAC resistance RA_(BP2), the output-terminal-side AC resistance RB_(BP1),and the output-terminal-side AC resistance RB_(BP2) are each set at avalue suitable for the operation of the plasma processing unit.Meanwhile, the variations <RA> and <RB> among a plurality of plasmaprocessing units defined by equations (14A′), (14A″), (14B′), and (14B″)are adjusted so that the effective power consumed in the plasma spacesof these units can be made substantially the same.

The plasma processing apparatus and the inspection method therefor ofthis embodiment have the same advantages as in the first to thirdembodiments. Moreover, because the feed plate 3 is included in themeasured region of the matching circuit 2A, the difference in theradiofrequency characteristics among the plurality of plasma processingunits can be further minimized compared to the embodiment not includingthe radiofrequency feeder (feed plate) 3 in the measured region. Thus,the effective power consumed in the plasma space of each plasmaprocessing unit can be made uniform among the plurality of the plasmaprocessing units, and the uniformity in the process results obtained byapplying the same process recipe to these plasma processing units can befurther improved.

It should be noted here that in each of the above-described first tofourth embodiments, the variation may be set at a value less than 0.4instead of less than 0.5. Also, the measuring point may be selected fromamong the points PR, PR2, PR3, and PR4.

Moreover, a switch or switches similar to the switches SW1, SW1′, andSW5, and a measuring terminal similar to the measuring terminals 61 and61′ for switching between the impedance meter AN and the radiofrequencygenerator 1 may be provided at the point PR in each of theabove-described embodiments.

Furthermore, these measuring points, switches, and the measuringterminals may be set in relation to the matching circuit 25.

Fifth embodiment

A plasma processing apparatus, plasma processing system, and aninspection method therefor will be explained below with reference to thedrawings.

FIG. 21 is a schematic diagram illustrating an overall structure of aplasma processing system according to this embodiment.

The plasma processing system of this embodiment is substantially acombination of plasma processing apparatuses 71 and 71′ which correspondto the plasma processing apparatus 71 of the first embodiment shown inFIG. 1 and a plasma processing apparatus 91 which corresponds to theplasma processing apparatus 91 according to the second to fourthembodiments shown in FIGS. 10 to 20. Like components are represented bythe same reference numerals, and explanations thereof are omitted.

The plasma processing system of this embodiment constitutes a part of aproduction line and includes the plasma processing apparatus 71, theplasma processing apparatus 91, and a plasma processing apparatus 71′,as shown in FIG. 21. The plasma processing apparatus 71 has three plasmaprocessing units 95, 96, and 97. The plasma processing apparatus 91 hastwo plasma processing units 95 and 96. The plasma processing apparatus71′ has three plasma processing units 95, 96, and 97.

The plasma processing apparatuses 71 and 71′ differ from that accordingto the first embodiment shown in FIG. 1 in that three plasma processingunits 95 to 97 each having substantially the same configuration as theplasma processing unit 95 of a dual-frequency excitation type describedin the second to fourth embodiments shown in FIGS. 10 to 20 are usedinstead of the plasma processing units 75 to 77. The plasma processingunits 95 to 97 of the fifth embodiment have substantially the samestructure.

Referring to FIG. 21, each of the plasma processing units 95 to 97 hasthe impedance measuring terminal 61 and the switch SW5 which areconnected to the impedance meter AN via a switch SW3. During themeasurement of the impedance, the switch SW3 connects only one of theplasma chambers 95, 96, and 97 to the impedance meter AN. The length ofa coaxial cable connecting the measuring terminal 61 to the switch SW3is set to be the same for all plasma processing units 95 to 97 so thatimpedance in the coaxial cables for the plasma processing units 95 to 97are set to be the same. As in the third embodiment shown in FIGS. 15 and17, the probe 105 of the impedance meter AN is detachably attached tothe measuring terminal 61.

Among the plasma processing units 95 to 97 in this embodiment, avariation <RA> is defined by equation (14A) below:<RA>=(RA _(max) −RA _(min))/(RA _(max) +RA _(min))  (14A)wherein RA_(max) and RA_(min) are the maximum and minimum values,respectively, among an input-terminal-side AC resistance RA₉₅ in theplasma processing unit 95, an input-terminal-side AC resistance RA₉₆ inthe plasma processing unit 96, and an input-terminal-side AC resistanceRA₉₇ in the plasma processing unit 97. The variation <RA> defined byequation (14A) is then set at a value less than 0.5. The variation <RA>can be adjusted by the methods (1) to (4) described above.

A variation <RB> is defined by equation (14B) below:<RB>=(RB _(max) −RB _(min))/(RB _(max) +RB _(min))  (14B)wherein RB_(max) and RB_(min) are the maximum and minimum values,respectively, among an output-terminal-side AC resistance RB₉₅ in theplasma processing unit 95, an output-terminal-side AC resistance RB₉₆ inthe plasma processing unit 96, and an output-terminal-side AC resistanceRB₉₇ in the plasma processing unit 97. The variation <RB> defined byequation (14B) is then set to a value less than 0.5. The variation <RB>can also be adjusted by the methods (1) to (4) described above.

In the plasma processing system of the present invention, for example, asubstrate 16, which has been preliminarily treated, is subjected to afirst layer deposition treatment in the plasma processing unit 95 of theplasma processing apparatus 71, is heat-treated in the annealing unit79, and is then annealed in the laser annealing unit 78. The treatedsubstrate 16 is subjected to second and third layer depositiontreatments in the plasma processing units 96 and 97.

The substrate 16 discharged from the plasma processing apparatus 71 istransferred into another treating apparatus not shown in the drawing, soas to apply a photoresist thereto by a photolithographic step.

Next, the substrate 16 is transferred into the plasma processingapparatus 91 and is plasma-etched in the processing units 95 and 96.Subsequently, the substrate 16 is transferred to another plasmaprocessing unit which is equivalent to the plasma processing apparatus91 but not shown in the drawing, and is subjected to a depositiontreatment.

The substrate 16 is then discharged from the plasma processing apparatusnot shown in the drawing and transferred into another treating apparatusalso not shown in the drawing so as to remove the resist layer and toperform photolithographic patterning thereon.

The substrate 16 is transferred to the plasma processing apparatus 71′and is sequentially subjected to first, second, and third depositiontreatments in the plasma processing units 95, 96, and 97. Finally, thetreated substrate 16 is discharged from the plasma processing system tobe subjected to after treatment.

The plasma processing system and the inspection method therefor of thisembodiment have the same advantages as those in the first and secondembodiments. Moreover, the variations in the input-terminal-side ACresistance RA and the output-terminal-side AC resistance RB in thematching circuits 2A of the plasma processing units 95 to 97 are set tobe less than 0.5. Thus, the difference in the radiofrequencycharacteristics among the plasma processing units 95 to 97 can beminimized, and the plasma processing units 95 to 97 can be maintainedwithin a predetermined range indicated by the impedance characteristic,thereby generating plasma of substantially the same density.

As a result, substantially the same plasma process results can beachieved by applying the same process recipe to the plasma processingunits 95 to 97. When applied to a deposition process, layers havingsubstantially the same layer characteristics, such as layer thickness,isolation voltage, and etching rate, can be manufactured using theplasma processing units 95 to 97. More specifically, the above-describedvariations are maintained at less than 0.5 so as to maintain thevariation in layer thickness among layers manufactured by these plasmaprocessing units 95 to 97 within ±7% using the same process recipe.Thus, the overall radiofrequency characteristics of the plasmaprocessing system can be optimized, and the plasma processing units 95to 97 can stably generate plasmas, achieving stable and uniformoperation.

As a result, a determination of process conditions based on therelationships between enormous amounts of data on these processingchambers 95, 96, and 97 and the results obtained by evaluation ofactually processed substrates is no longer necessary.

Thus, in installing new systems and during inspection of installedsystems, the time required for adjusting these processing chambers 95,96, and 97 to obtain substantially the same results using the sameprocess recipe can be significantly reduced compared with an inspectionmethod requiring actual deposition on the substrate 16. Moreover,according to this embodiment, the plasma processing system can bedirectly evaluated in situ in a shorter period of time compared to aconventional two-stage evaluation requiring the steps of firstprocessing the substrate and then evaluating the performance based onthe evaluation of the processed substrate. Moreover, in this embodiment,inspection by layer deposition on substrates is performed to determinethe process recipe when the plasma process apparatus is installed. Sincethe plasma processing units 95 to 97 have the same radiofrequencycharacteristics, the layer deposition may be performed in only one ofthe units. In the maintenance of the plasma processing apparatus, actuallayer deposition is not required because the radiofrequencycharacteristics of the plasma processing units are controlled within thepredetermined value. In contrast, these plasma process units must beindependently evaluated if conventional evaluation methods are appliedto the conventional plasma processing apparatuses.

Accordingly, a shutdown of the production line for several days orseveral weeks to validate and evaluate the operation of the plasmaprocessing system is no longer necessary. The production line,therefore, has high productivity with reduced costs since the cost ofsubstrates for inspection, the cost of processing the substrates forinspection, and the labor cost for workers involved with the adjustmentcan be reduced.

In the plasma processing system of this embodiment, overallradiofrequency characteristics of the plasma processing units 95 to 97can be optimized by adjusting the input-terminal-side AC resistance RAand output-terminal-side AC resistance RB of each of the plasmaprocessing units 95 to 97. Thus, the plasma processing units 95 to 97can be stably operated, and power loss in the matching circuit 2A and inthe vicinity of matching circuit 2A can be reduced even when power of afrequency higher than the frequency conventionally used, i.e., 13.56MHz, is supplied from the radiofrequency generator 1. Accordingly, powercan be efficiently introduced into the plasma generating space betweenthe plasma excitation electrode 4 and the susceptor electrode 8. When afrequency equal to the frequency conventionally used is supplied, theeffective power consumed in the plasma generating spaces in the plasmaprocessing units 95 to 97 can be increased compared to conventionalplasma processing apparatuses.

Consequently, the processing rate of the plasma processing system as awhole can be improved by using higher plasma excitation frequencies.When applied to a deposition process such as a plasma enhanced CVDprocess, deposition rate in all the plasma processing units 95 to 97 canbe further improved. Since the plasma processing units 95 to 97 can bestably operated, the plasma processing apparatuses 71, 91, and 71′ canalso be stably operated to improve the operational stability of thewhole plasma processing system These advantages can be simultaneouslyachieved in all the plasma processing units.

In the plasma processing units 95 to 97, effective power consumed in theplasma generating spaces is increased to improve the planar uniformityof the plasma processing on the substrate 16. When applied to adeposition process such as a plasma-enhanced CVD or a sputteringprocess, the distribution in a planar direction in the layer thicknesscan be improved, and layer characteristics such as isolation voltage,resistance against etching, density (hardness) of the deposited layer,can be improved as a result of increased plasma density.

Since effective power consumed in the plasma space can be improvedcompared to conventional plasma processing systems when the frequencyconventionally used is supplied, the plasma processing system as a wholeexhibits an improved power consumption efficiency, requiring less powerto obtain the same processing rate or layer characteristics. Theseadvantages can be achieved in all the plasma processing unitsconstituting the system. Accordingly, this plasma processing systemachieves reduction in power loss and operating cost, and furtherimproves the productivity. Since the time required for processing isreduced, power consumption can be reduced and emission of carbon dioxidewhich adversely affects the environment can be reduced.

In the plasma processing system of this embodiment, each of the plasmaprocessing units 95 to 97 is provided with the measuring terminal 61 andthe switch SW5 at the point PR3 of the matching circuit 2A. A singleimpedance meter AN is switchably connected to the measuring terminal 61and the switch SW5 via the switch SW3. During measurement of theimpedance characteristics of the plasma processing units in the plasmaprocessing system, the matching circuit 2A need not be detached from theradiofrequency generator 1 and the feed line 1A as in the first and thesecond embodiments. Moreover, the impedance characteristics, theinput-terminal-side AC resistance RA, and the output-terminal-side ACresistance RB of the plurality of plasma processing units can bemeasured by using a single impedance meter AN.

Thus, the impedance characteristics of the plasma processing units 95 to97 can be measured easily, and the AC resistances RA and RB can befurther effectively measured.

The impedance between the measuring terminal 61 and the switch SW3 isadjusted to be the same among the plasma processing units 95 to 97constituting the plasma processing apparatuses 71, 71′, and 91. Sincethe impedance between the measuring terminal 61 and the switch SW3 isset to be equal to the impedance measured at the point PR2 at theradiofrequency generator 1 side, the readings of the impedance meter ANmeasured by suitably operating the switches SW1, SW2, and SW3, can bedeemed as the impedance measured at the point PR2 at the radiofrequencygenerator 1 side.

Since the difference in the impedance characteristics from the measuringterminal 61 to the switch SW3 of the plasma processing units 95 to 97can be disregarded, the input-terminal-side AC resistance RA and theoutput-terminal-side AC resistance RB can be measured more precisely andefficiently without correction or conversion. Thus, theinput-terminal-side AC resistance RA and the output-terminal-side ACresistance RB can be efficiently and further accurately measured.

In this embodiment, the switches SW3 and SW5 may cooperate tosequentially switch the connection to the plasma processing units 95 to97. Moreover, instead of two switches SW1 and SW2, a single switch whichsets the impedance between the branching point to the point PR equal tothe impedance between the branching point to the probe may be provided.

Although in the above-described embodiments, the AC resistances RA andRB are set in relation to the plasma excitation electrode 4 of eachplasma processing unit, the AC resistances RA and RB may be set inrelation to the susceptor electrode 8. In such a case, measuring pointsPR′, PR3′, and PR4′ of the matching circuit 25 as shown in FIGS. 11 and15 are used.

Moreover, the present invention can be applied to a plasma processingapparatus of an inductive coupled plasma (ICP) type or a radial lineslot antenna (RLSA) type, and to a processing apparatus for reactive ionetching (RIE).

In each of the above-described embodiments, the matching circuit 2A andthe radiofrequency generator 1 are respectively provided for each of theplasma processing units 95 to 97, as illustrated in FIG. 22, and each ofthe matching circuits 2A is connected to the single impedance meter ANvia the switch SW4. Alternatively, as shown in FIG. 23, matchingcircuits 2A of the plasma processing units 95, 96, and 97 may beswitchably connected to the same radiofrequency generator.Alternatively, as shown in FIG. 24, the plasma processing units 95 to 97may be switchably connected to the same matching circuit 2A.

Alternatively, two separate impedance meters AN for measuring theinput-terminal-side AC resistance RA and the output-terminal-side ACresistance RB, respectively, may be provided to be connected to theplasma processing unit. In such a case, a switch may be provided toswitch between measuring of the input-terminal-side AC resistance RA andthe measuring of the output-terminal-side AC resistance RB.

In the above-described embodiments, the frequency for measuring theinput-terminal-side AC resistance RA and the output-terminal-side ACresistance RB oscillated by the impedance meter AN is set at the samefrequency as the power frequency f_(e) supplied from the radiofrequencygenerator 1. Thus, the characteristics of the plasma processing units 95to 97 can be adjusted to be within a predetermined range, and thedifference in the radiofrequency characteristics of these units can bereduced. The plasma processing units 95 to 97 thereby consumesubstantially the same power in their plasma generating spaces.

Sixth Embodiment

Next, a performance validation system for a plasma processing apparatusor a plasma processing system according to an embodiment of the presentinvention will be described below with reference to the drawings. In thefollowing description, a person who distributes and maintains the plasmaprocessing apparatus is referred to as a “maintenance engineer”.

FIG. 25 is a diagram illustrating the configuration of the performancevalidation system for the plasma processing apparatus or systemaccording to this embodiment.

Referring to FIG. 25, the performance validation system comprises acustomer terminal (client terminal) C1, an engineer terminal (clientterminal) C2, a server computer (hereinafter simply referred to as“server”) S which functions as operational performance informationprovider, a database computer (hereinafter simply referred to as“database”) D which stores information, and a public line N. Thecustomer terminal C1, the engineer terminal C2, the server S, and thedatabase D are linked to one another via the public line N.

The terminals C1 and C2 communicate with the server S using a widespreadInternet communication protocol, such as TCP/IP or the like. Thecustomer terminal C1 serves as a customer-side information terminal forvalidating, via the public line N, the state of the performance of theplasma processing units which the customer purchased from themaintenance engineer. The customer terminal C1 also has a function toview an information web page which is a “plasma chamber performanceinformation page” stored in the server S. The engineer terminal C2allows the maintenance engineer to upload “input-terminal-side ACresistance RA information” and “output-terminal-side AC resistance RBinformation” which partially constitutes the “performance information”and to receive e-mail sent from the customer through the customerterminal C1.

Herein, the structure of the plasma processing apparatus or system to beevaluated is identical to any one of the structures according to theabove-described first to fifth embodiments. The configuration of theplasma processing apparatus, such as the number of plasma processingunits in the apparatus, can be set as desired.

The server S communicates via a modem when the public line N is ananalog line and via a dedicated terminal adapter or the like when thepublic line N is a digital line such as an integrated services digitalnetwork (ISDN).

The server S is a computer that provides performance information. Theserver S transmits the performance information to the customer terminalC1 using an Internet communication protocol upon the request from thecustomer terminal Cl. Herein, each of the customers who purchased theplasma chambers receives a “browsing password” for viewing theperformance information before the plasma processing apparatus isdelivered to the customer from the maintenance engineer. This passwordis required when the customer desires to view operation and maintenanceinformation which is part of the performance information, and the serverS sends the operation and maintenance information to the customerterminal C1 only when a registered browsing password is provided.

The above-described “performance information”, details of which will bedescribed in a later section, comprises information regarding models ofthe plasma processing units constituting the plasma processing apparatusor system available from the maintenance engineer, information regardingquality and performance of each model in the form of specifications,information regarding parameters indicative of quality and performanceof specific apparatuses delivered to customers, and informationregarding parameters and maintenance history.

The information regarding quality and performance of specificapparatuses and the information regarding parameters and maintenancehistory, are accessible only from the customers provided with “browsingpasswords”.

The performance information described above is provided in the form of“operation and maintenance information” and “standard performanceinformation”. The operation and maintenance information is a type ofinformation provided from the maintenance engineer or the customer tothe server S to indicate the actual state of operation and maintenance.The standard performance information is a type of information stored inthe database D and serves as a catalog accessible from potentialcustomers. The “standard performance information” is an objectivedescription regarding the plasma processes performed in the plasmaprocessing unit and allows prediction of the deposition state whenapplied to deposition processes such as plasma-enhanced CVD andsputtering processes.

In this embodiment, the “standard performance information” is stored inthe database D.

Upon the request from the customer terminal C1 to view the “performanceinformation”, the server S retrieves the requested “standard performanceinformation” from the database D and sends the information to thecustomer terminal C1 of the customer in the form of a performanceinformation page. When a request to view the “performance information”is transmitted along with the browsing password of the customer, theserver S retrieves the requested “standard performance information” fromthe database D as described above, composes the “performanceinformation” by combining the retrieved “standard performanceinformation” and the “operation and maintenance information” providedfrom the maintenance engineer through the engineer terminal C2, andtransmits the “performance information page” to the customer terminalC1.

The database D stores the “standard performance information”, which ispart of the “performance information”, according to the models of theplasma chambers of the plasma processing apparatus or plasma processingsystem, reads out the “standard performance information” in response toa search request sent from the server S, and transmits the retrievedinformation to the server S. Although only one server S is illustratedin FIG. 25, a plurality of servers are provided in this embodiment. Inthis respect, it is useful to store general purpose “standardperformance information” in the database D instead of these servers inorder for the information to be shared among the plurality of serversmanaged by maintenance engineers from different locations.

Next, an operation of the performance validation system for the plasmaprocessing apparatus or the plasma processing system having theabove-described structure will be explained in detail with reference tothe flowchart shown in FIG. 26. The flowchart illustrates the process ofproviding the “performance information” executed at the server S.

Generally, the maintenance engineer presents, as a reference forpurchase, the “standard performance information” contained in the“performance information” of a model of the plasma chamber themaintenance engineer is attempting to sell to the customer. The customeris able to understand the performance of the plasma processing unit andpossible plasma processes using the plasma processing unit through this“standard performance information”.

The customer who purchased the plasma processing apparatus or system isprovided with the “standard operation information”, which serves as thereference during the use of the plasma chambers, and the “operation andmaintenance information”, which serves as the parameters of theoperation. The customer, i.e., the user of the plasma chambers, mayvalidate the operation of the plasma processing units by comparing the“standard performance information” and the “operation and maintenanceinformation” so as to be informed of the state of the plasma processingand to determine whether it is necessary to perform maintenance.

For example, a customer who is considering purchasing a new plasmaprocessing apparatus or system from the maintenance engineer may accessthe server S to easily confirm the “standard performance information” ofthe plasma processing apparatus or system the customer is intending topurchase as follows.

The customer who desires to view the “performance information” firstsends from the customer terminal C1 a request for access to the server Sbased on an IP address of the server S set in advance.

Upon receiving the request for access (Step S1), the server S transfersa main page CP to the customer terminal C1 (Step S2).

FIG. 27 shows an example of the main page CP sent from the server S tothe customer terminal C1 through the steps described above. The mainpage CP comprises model selection buttons K1 to K4 for displaying the“standard performance information” contained in the “performanceinformation” according to models available from the maintenance engineerand a user button K5 for requesting the display of a customer pageexclusive to the customer to whom the maintenance engineer delivered theplasma processing apparatus.

For example, a customer may select one of the model selection buttons K1to K4 using a pointing device (for example, a mouse) of the customerterminal C1 so as to specify which model of the plasma chamber thecustomer desires to obtain the information about. Such a selection isregarded as the request for accessing the “standard performanceinformation” among the “performance information”, and a request to thateffect is sent to the server S.

Upon receipt of the request (Step S3), the server S sends the customerterminal C1 a subpage containing the requested information on theselected model. That is, when display of “standard performanceinformation” is requested by specifying a model (line A in FIG. 26), theserver S retrieves data such as “vacuum performance”, “gascharge/discharge performance”, “temperature performance”, and“electrical performance of the plasma processing chamber”, and dataregarding variations in these parameters affected in the plasmaprocessing apparatus or system from the database D and sends thecustomer terminal C1 a specifications page CP1 shown in FIG. 28containing these data (Step S4).

As shown in FIG. 28, the specifications page CP1 comprises an apparatusmodel section K6 indicating the selected model of the apparatus, avacuum performance section K7, a gas charge/discharge performancesection K8, a temperature performance section K9, and an electricalperformance section K10 indicating the electrical performance of theplasma processing chamber. These constitute the “standard performanceinformation” of the selected model and each contains the followingdescriptions.

In the vacuum performance section K7, the following items are displayed:

-   -   ultimate vacuum: 1×10⁻⁴ Pa or less; and    -   operational pressure: 30 to 300 Pa.

In the gas supply/discharge performance section K8, the following itemsare displayed:

-   -   maximum gas flow rates:

SiH₄   100 SCCM, NH₃   500 SCCM, N₂ 2,000 SCCM;

-   -    and    -   discharge property: 20 Pa or less at a flow of 500 SCCM.

In the temperature performance section K9 the following items aredisplayed:

-   -   heater temperature: 200 to 350±10° C.; and    -   chamber temperature: 60 to 80±2.0° C.

Herein, the SCCM (standard cubic centimeters per minute) valuesrepresent the corrected gas flow rates at standard conditions (0° C. and1,013 hPa) and the unit thereof is cm³/min.

A variation in each of the above-described parameters P among theplurality of the plasma processing units constituting the plasmaprocessing apparatus or system is defined by relationship (10B) below:(P_(max)−P_(min))/(P_(max)+P_(min))  (10B)wherein P_(max) represents the maximum value of a particular parameteramong the plurality of the plasma processing units and P_(min)represents the minimum value of the particular parameter among theplurality of the plasma processing units. The upper limit of thevariation in the plasma processing apparatus or system is displayed foreach of the parameters.

In the electrical performance section K10, the setting ranges of theinput-terminal-side AC resistance RA, the output-terminal-side ACresistance RB, and the variations in the input-terminal-side ACresistance RA and the output-terminal-side AC resistance RB described inthe first to fifth embodiments are displayed. In addition to these,values such as a resistance R_(e) and a reactance X_(e) of the plasmaprocessing chamber at the power frequency f_(e), a plasma capacitance C₀between the plasma excitation electrode 4 and the susceptor electrode 8,a loss capacitance C_(x) between the plasma excitation electrode 4 andeach of the components which are the ground positions of the plasmaprocessing unit, the first series resonant frequency f₀ described below,and the like are included in the section K10. Furthermore, thespecification page CP1 includes a performance guarantee statement suchas “we guarantee that each of the parameters is within the setting rangedescribed in this page upon the delivery of the plasma chamber”.

In this manner, the overall radiofrequency electrical characteristics ofthe plasma processing units and the variation in the electricalcharacteristics of the plasma processing units can be presented to apotential purchaser as a novel reference which has never been consideredbefore. The performance information can be printed out at the customerterminal C1 or the engineer terminal C2 to make a hard copy thereof sothat the information can be presented in the form of a catalog orspecifications describing the performance information containing theabove-described detailed information. Since the setting ranges of theinput-terminal-side AC resistance RA and the output-terminal-side ACresistance RB, the resistance R_(e), the reactance X_(e), thecapacitances C₀, C_(x), and the performance guarantee statement arepresented to a potential purchaser through a terminal such as customerterminal C1, through a catalog, or through a specification, thepotential purchaser may judge the performance of the plasma processingunits just as if the customer is examining electrical components and maythen purchase the plasma processing apparatus or system from themaintenance engineer based on that judgement.

After the server S completes the transmission of the above-describedsubpage to the customer terminal C1, the server S waits for the requestto display another subpage (Step S3) if a log-off request from thecustomer terminal C1 is not received (Step S5). If a log-off requestfrom the customer terminal C1 is received by the server S, the server Sterminates the interaction with the customer terminal C1 (Step S5).

Now, the definition of the first series resonant frequency f₀ isexplained with reference to FIG. 15.

First, the dependency of the impedance of the plasma processing chamberon the frequency is measured. During measuring, the switch SW1 connectsa point PR5 to the measuring terminal 61′, and the switch SW5disconnects the matching circuit 2A from the radiofrequency generator 1and the impedance meter AN. The frequency oscillated by the impedancemeter AN is varied over a predetermined range including the powerfrequency f_(e) to measure the vector quantity (Z, θ) of the impedancein the plasma processing chamber. For example, the frequency is variedin the range of 1 to 100 MHz to include the power frequency f_(e) whichis set at 13.56 MHz, 27.12 MHz, 40.68 MHz, or the like.

The impedance Z and the phase θ are plotted versus frequency to give animpedance characteristic curve and a phase curve. The first seriesresonant frequency f₀ is then defined as the lowest frequency of thefrequencies at the minima of the impedance Z, i.e., the frequency at azero phase when the phase curve first changes from negative to positiveas the frequency is elevated.

The customer who purchased and obtained the plasma chamber from themaintenance engineer can easily check the “performance information” ofthe specific plasma processing unit of the plasma processing apparatusor system that the customer purchased, by accessing the server S asbelow.

When the customer and the maintenance engineer enter into a salescontract, a customer ID, which is unique to the individual customer anda “customer password (browsing password)” for accessing the “operationand maintenance information” of the plasma processing units constitutingthe plasma processing apparatus or system are provided to the customerfrom the maintenance engineer. The customer ID may be associated withthe serial number of the purchased plasma processing apparatus or systemor with the serial number of the plasma processing unit constituting theplasma processing apparatus or system. The server S sends the “operationand maintenance information” to the customer terminal C1 only when theregistered browsing password is provided.

A customer who wants to access the information selects the user buttonK5 in the above-described main page CP to send the request for thedisplay of a customer page to the server S.

Upon receiving the request for the display (Step S3-B), the server Ssends a subpage prompting the customer to input the “browsing password”(Step S6). FIG. 29 illustrates a customer page CP2. The customer pageCP2 comprises a customer ID input field K11 and a password input fieldK12.

The customer page CP2 prompting the customer to input the browsingpassword is displayed at the customer terminal C1. In response to theprompt, the customer enters the “browsing password” and the “customerID”, which are provided from the maintenance engineer, through thecustomer terminal C1 so as to allow the server S to identify the plasmaprocessing units constituting the plasma processing apparatus or systemthat the customer has purchased.

At this stage, the customer enters the customer ID into the customer IDinput field K11 shown in FIG. 29 and the browsing password into thepassword input field K12 shown in FIG. 29. The server S sends the“operation and maintenance information” subpage previously associatedwith that “browsing password” to the customer terminal C1 (Step S9),only when the server S receives the registered “customer ID” and the“browsing password” from the customer terminal C1 (Step S7).

In other words, the “operation and maintenance information” isaccessible only by the specific customer who signed the sales contractfor the plasma processing apparatus or system, i.e., who is inpossession of the registered “browsing password”. A third party usingthe server S cannot access the “operation and maintenance information”.Although the maintenance engineer often exchanges sales contracts with aplurality of customers simultaneously and delivers a plurality of plasmaprocessing units for these customers simultaneously, each of thecustomers is provided with a “browsing password” unique to the customer,unique to the plasma processing apparatus or system, or unique to eachone of the plasma processing units constituting the plasma processingapparatus or system and is capable of individually accessing the“operation and maintenance information” associated with the “browsingpassword” assigned to that customer.

Thus, it becomes possible to securely prevent confidential informationregarding the purchase of the plasma chamber from being made known toother customers. Furthermore, the plasma processing apparatus, theplasma processing system, the plasma processing chambers thereof can beseparately identified even when they are delivered simultaneously.

If the server S does not receive a registered “browsing password” (StepS7), a message refusing the access and prompting the customer tore-enter the “browsing password” is sent to the customer terminal C1(Step S8). If the customer erroneously entered the “browsing password”,the customer may take this opportunity to reenter a correct password toaccess the “operation and maintenance information”.

If the customer ID and the password are authorized (Step S7), the serverS retrieves data corresponding to the requested information from thedatabase D and sends it to the customer terminal C1 in the form of asubpage. That is, when the server S receives a request from the customerterminal C1 requesting display of the “standard performance information”and the “operation and maintenance information” of the plasma processingunits of the specific plasma processing apparatus or system identifiedby the customer ID, data such as “vacuum performance”, “gascharge/discharge performance”, “electrical performance of the plasmaprocessing chamber”, and the like are retrieved from the database D byspecifying the apparatus model, and a specifications page (subpage) CP3containing these data is sent to the customer terminal C1 (Step S9).

FIG. 30 illustrates a maintenance history page (subpage) CP3 containing“operation and maintenance information”, which is sent from the server Sto the customer terminal C1. As shown in FIG. 30, the maintenancehistory page CP3 comprises a serial number section K13 indicating theserial numbers of the plasma processing apparatus or system and theplasma processing chambers thereof, the vacuum performance section K7,the gas charge/discharge performance section K8, the temperatureperformance section K9, the electrical performance section K10, a vacuumperformance maintenance section K14, a gas charge/discharge performancemaintenance section K15, a temperature performance maintenance sectionK16, and an electrical property maintenance section K17. In the sectionsK14 to K17, the “operation and maintenance information” of theindividual plasma processing units is displayed.

In the vacuum performance maintenance section K14, the following itemsare displayed:

-   -   ultimate vacuum: 1.3×10⁻⁵ Pa or less;    -   operational pressure: 200 Pa.

In the gas charge/discharge performance maintenance section K15, thefollowing items are displayed:

-   -   gas flow rates:

SiH₄  40 SCCM, NH₃ 160 SCCM, N₂ 600 SCCM;

-   -    and    -   discharge property: 6.8×10⁻⁷ Pa.m³/sec.

In the temperature performance maintenance section K16, the followingitems are displayed:

-   -   heater temperature: 302.3±4.9° C.; and    -   chamber temperature: 80.1±2.1° C.

The variation in each of the above-described parameters P among theplurality of the plasma processing units constituting the plasmaprocessing apparatus or system is defined by relationship (10B) below:(P_(max)−P_(min))/(P_(max)+P_(min))  (10B)wherein P_(max) represents the maximum value of a particular parameteramong the plurality of the plasma processing chambers and P_(min)represents the minimum value of the particular parameter among theplurality of the plasma processing chambers. Setting ranges of thevariations calculated as above are displayed in the correspondingparameter sections.

A “detail” button K18 is provided in each of the sections K14, K15, K16,and K17. The customer may access the detailed information of the desiredsection by selecting one of the “detail” buttons K18 provided in thedesired section.

When the customer submits a display request by selecting the “detail”button K18, a detailed maintenance page CP4 including detailedinformation on the maintenance history is transmitted from the server Sto the customer terminal C1.

FIG. 31 shows the detailed maintenance page CP4 (subpage) transmittedfrom the server S to the customer terminal C1.

FIG. 31 illustrates the detailed maintenance page CP4 for the electricalproperty maintenance section K17.

As shown in FIG. 31, the detailed maintenance page CP4 comprises theserial number display sections K13 for displaying the serial numbers ofthe plasma processing units and the plasma processing apparatus orsystem purchased by the customer, the electrical performance sectionK10, and the electrical property maintenance section K17. In theelectrical property maintenance section K17, the values of theparameters P measured during maintenance are displayed in thecorresponding parameter sections of each plasma processing unit, and thevariations among these measured values are displayed in the variationsection for each of the plasma processing apparatus or system.

In the electrical performance section K10, setting ranges for theinput-terminal-side AC resistance RA and output-terminal-side ACresistance RB described in the first to fifth embodiments are displayed.In the electrical property maintenance section K17, the measured valuesof the input-terminal-side AC resistance RA and the output-terminal-sideAC resistance RB, and the variation calculated from these values aredisplayed. In addition to these, the resistance R_(e) and reactanceX_(e) of the plasma processing chamber at the power frequency f_(e), theplasma capacitance C₀ between the plasma excitation electrode 4 and thesusceptor electrode 8, the loss capacitance C_(X) between the plasmaexcitation electrode 4 and the ground potential portion of the plasmachamber, etc., are displayed.

As shown in FIGS. 30 and 31, in both the maintenance history page CP3and the detailed maintenance page CP4, the “operation and maintenanceinformation” and the “standard performance information” comprising datasuch as the “vacuum performance”, “gas charge/discharge performance”,“temperature performance”, “electrical performance”, etc. retrieved fromthe database D, are displayed together. Thus, the customer can view the“operation and maintenance information” while referring to the “standardperformance information”. The customer may use the “standard performanceinformation” as the reference during use and the “operation andmaintenance information” as the parameter indicative of the actual stateof the operation. By comparing the “standard performance information” tothe “operation and maintenance information”, the customer can validatethe operation of the plasma processing units of the plasma processingapparatus or system, determine whether it is necessary to performmaintenance, and be informed of the state of the plasma processing.

If the server S does not receive a log-off request from the customerterminal C1 after transmission of the subpages CP3 and CP4 to thecustomer terminal C1 (Step S5), the server S transmits an invalidconnection message to the customer terminal C1 (Step S8) to promptreentry of the “customer password” or to wait for the next displayrequest (Step S3). If the server S receives the log-off request from thecustomer terminal C1 (Step S5), the communication with the customerterminal C1 is terminated.

As described above, according to the present invention, the performancevalidation system for the above-described plasma processing apparatuscomprises a customer terminal, an engineer terminal, and an informationprovider. The customer terminal requests browsing of performanceinformation to the information provider via a public line, a maintenanceengineer uploads the performance information to the information providerthrough the engineer terminal, and the information provider provides theperformance information uploaded from the engineer terminal to thecustomer terminal upon the request from the customer terminal. Theperformance information contains the input-terminal-side AC resistanceRA, the output-terminal-side AC resistance RB, and the variations in theAC resistances RA and RB among the plasma processing units constitutingthe plasma processing apparatus or system. The performance informationcan be output as a catalog or a specification document so that acustomer may be provided with a basis for making purchasing decisions.The customer may also view the performance information comprising thestandard performance information and the operation and maintenanceinformation at the information terminal via a public line. Thus, it ispossible to readily provide the customer with the information regardingthe operation, performance, and maintenance of the plasma processingunits of the plasma processing apparatus or system in use.

Moreover, because the performance information includes the informationregarding the input-terminal-side AC resistance RA, theoutput-terminal-side AC resistance RB, and the variations in the ACresistances RA and RB among the plasma processing units, the performanceof the plasma processing apparatus or system can be readily evaluated. Acustomer who is considering purchasing a new plasma processing apparatusor system can be provided with a basis for making purchasing decisions.Furthermore, the performance information may also be output as a catalogor a specification document available to the customer.

EXAMPLES

In the following examples, variations in input-terminal-side ACresistance RA and output-terminal-side AC resistance RB among aplurality of plasma processing units were adjusted to be less thancertain values so as to observe changes in layer characteristics duringa deposition process.

The plasma processing apparatus used was of a dual-frequency excitationtype. Four different matching circuits were sequentially connected tothe same plasma processing chamber to eliminate the difference resultingfrom the mechanical structure of the plasma processing chamber.

The plasma processing apparatus had 25 cm square electrodes 4 and 8 of aparallel plate type. The interelectrode distance was set at 15 mm, thepower was set at 600 W, and the power frequency f_(e) was set at 40.68MHz.

First, the input-terminal-side AC resistance RA and theoutput-terminal-side AC resistance RB of four different matchingcircuits were measured. In measuring the input-terminal-side ACresistance RA and the output-terminal-side AC resistance RB, thematching circuit 2A was disconnected from the feed plate 3 and the feedline 1A, and the AC resistances RA and RB were measured from the pointPR3 and PR, respectively, as in the second embodiment.

The frequency from the impedance meter was varied over the range of 1 to100 MHz to determine the vector quantity of the impedance, and the ACresistances RA and RB were calculated from the values Z and θ at thepower frequency 40.68 MHz.

Matching Circuit 1 had a structure identical to the matching circuit 2Ain the first embodiment shown in FIG. 3. In Matching Circuit 1, theinductance of the inductance coil 23 made of a copper pipe plated withsilver was 372 nH, the output-terminal-side AC resistance RB at thepower frequency f_(e) as a parasitic resistance component was 5.5 Ω, andthe input-terminal-side AC resistance RA as a parasitic resistancecomponent was 0.54 Ω.

In Matching Circuit 2, two inductance coils 23, each identical to thatof Matching Circuit 1, were connected in parallel so as to set the totalinductance at 370 nH. The output-terminal-side AC resistance RB at thepower frequency f_(e) as a parasitic resistance component was 3.2 Ω, andthe input-terminal-side AC resistance RA as a parasitic resistancecomponent was 0.55 Ω.

In Matching Circuit 3, four inductance coils 23, each identical to thatof Matching circuit 1, were connected in parallel sodas to set the totalinductance at 370 nH. The output-terminal-side AC resistance RB at thepower frequency f_(e) as a parasitic resistance component was 1.6 Ω, andthe input-terminal-side AC resistance RA as a parasitic resistancecomponent was 0.52 Ω.

Matching Circuit 4 had the inductance coil 23 composed of a copper pipehaving a larger diameter compared to the inductance coil 23 of MatchingCircuit 1. The total inductance was set at 370 nH, theoutput-terminal-side AC resistance RB at the power frequency f_(e) as aparasitic resistance component was 4.1 Ω, and the input-terminal-side ACresistance RA as a parasitic resistance component was 0.54 Ω.

The above-described four matching circuits were sequentially connectedto the same plasma processing chamber, and silicon nitride layers weredeposited according to the same process recipe to measure the variationsin the layer thickness as below:

-   (1) Depositing a SiN_(x) layer on a 6-inch glass substrate by a    plasma-enhanced CVD;-   (2) Patterning a resist layer by photolithography;-   (3) Dry-etching the SiN_(x) layer with SF₆ and O₂;-   (4) Removing the resist layer by O₂ ashing;-   (5) Measuring the surface roughness of the SiN_(x) layer using a    contact displacement meter to determine the layer thickness;-   (6) Calculating the deposition rate from the deposition time and the    layer thickness; and-   (7) Measuring the planar uniformity of the layer at 16 points on the    substrate surface.

The deposition conditions were as follows:

Substrate temperature: 300° C.

Gas pressure: 100 Pa

SiH₄ flow rate: 40 SCCM

NH₃ flow rate: 160 SCCM

N₂ flow rate: 600 SCCM

The results are shown in Table 1.

TABLE 1 Matching Matching Matching Matching Circuit 1 Circuit 2 Circuit3 Circuit 4 Input-terminal-side AC 0.54 0.55 0.52 0.54 resistance RA (Ω)Output-terminal-side 5.52 3.17 1.62 4.13 AC resistance RB (Ω) Inductanceof the coil 372 370 370 370 (nH) Deposition rate 184 224 237 207(nm/min)

Example 1

Matching Circuits 2 and 3 above were selected in Example 1.

Matching Circuits 2 and 3 exhibited the highest deposition rate, and thevariation in the deposition rate was 2.8%, i.e., less than 3%. Thevariation in the output-terminal-side AC resistance RB according toequation (14B) was 0.32, i.e., less than 0.4.

Example 2

Matching Circuits 1, 2, and 3 were selected in Example 2.

Matching Circuits 1, 2, and 3 exhibited the second highest depositionrate. However, the variation in the deposition rate was 12.6%, i.e.,more than 10%. The variation in the output-terminal-side AC resistanceRB according to equation (14B) was 0.55, i.e., not less than 0.5.

Example 3

Matching Circuits 2, 3, and 4 were selected in Example 3.

The variation in the deposition rate was 6.8%, i.e., less than 7%. Thevariation in the output-terminal-side AC resistance RB according toequation (14B) was 0.44, i.e., less than 0.5.

These results are shown in Table 2.

TABLE 2 Example 1 Example 2 Example 3 (2, 3) (1, 2, 3) (2, 3, 4)Variation <RA> 0.028 0.019 0.028 Variation <RB> 0.32 0.55 0.44 Variationin the 2.8 12.6 6.75 deposition rate (%)

Layers of silicon nitride are used as gate insulating layers inthin-film-transistor liquid-crystal devices (TFT-LCDs) and as insulatinglayers in storage capacitors loaded to maintain the voltage applied tothe liquid crystal at a satisfactory level. The property of the siliconnitride layer affects the contrast, i.e., the ratio of the maximum tominimum luminance values in a TFT-LCD as a product, and a variation of10% in the thickness of the silicon nitride layers results in avariation of approximately 50 in the contrast. That is, the contrastvaries over the range of 200 to 250 among a plurality of products.

When the variations in the input-terminal-side AC resistance RA andoutput-terminal-side AC resistance RB are not more than 0.5, thevariation in deposition characteristics can be maintained at 10% orless, and a variation in the contrast in the TFT-LCD as a product can bemaintained at about 50 or less.

When the variations in the input-terminal-side AC resistance RA andoutput-terminal-side AC resistance RB are not more than 0.45, thevariation in deposition characteristics can be maintained at 7% or less,and a variation in the contrast in the TFT-LCD as a product can bemaintained at about 30 or less.

When the variations in the input-terminal-side AC resistance RA andoutput-terminal-side AC resistance RB are not more than 0.4, thevariation in deposition characteristics can be maintained at 3% or less,and a variation in the contrast in the TFT-LCD as a product can bemaintained at about 10 or less.

As demonstrated above, the difference between different plasmaprocessing units can be minimized by adjusting the variations in theinput-terminal-side AC resistance RA and the output-terminal-side ACresistance RB.

According to the plasma processing apparatus, the plasma processingsystem, the performance validation system therefor, and the inspectionmethod therefor of the present invention, the input- and output-terminal-side AC resistances RA and RB as radiofrequency characteristicsare optimized to minimize the difference between the plasma processingunits. Thus, sufficiently the same plasma results can be achieved byapplying the same process recipe. Moreover, the process rate can beimproved by increasing the plasma excitation frequency, the uniformityof the plasma process in the planar direction of the substrate isenhanced, and the layer characteristics, power consumption efficiencyand productivity can be improved. The plasma processing apparatus andsystem can be readily maintained at an optimum operating state.Furthermore, materials for judging the performance of the plasmaprocessing apparatus and system can be provided for customers at thetime of purchase. The information regarding the performance apparatus orsystem can be output as a catalog or a specification document.

1. An inspection method for a plasma processing apparatus including aplurality of plasma processing units, each of the plurality of plasmaprocessing units comprising: a plasma processing chamber including anelectrode to excite a plasma; a radiofrequency generator to supplyradiofrequency power to the electrode; and a matching circuit to matchimpedances of the plasma processing chamber and the radiofrequencygenerator, the matching circuit having an input terminal connected tothe radiofrequency generator, an output terminal connected to theelectrode, and a connection point provided between the input terminaland the output terminal, the matching circuit being connected to aground potential portion via the connection point, the methodcomprising: inspecting whether a variation <RA> among the plurality ofplasma processing units defined by a first equation below is within afirst predetermined range:<RA>=(RA _(max) −RA _(min))/(RA _(max) +RA _(min)) where RA_(max) andRA_(min) are maximum and minimum values, respectively, of AC resistancesRA in the matching circuits of the plurality of plasma processing unitsmeasured from an input-terminal-side of the matching circuits; andinspecting whether a variation <RB> among the plurality of plasmaprocessing units defined by a second equation below is within a secondpredetermined range:<RB>=(RB _(max) −RB _(min))/(RB _(max) +RB _(min)) where RB_(max) andRB_(min) are maximum and minimum values, respectively, of AC resistancesRB in the matching circuits of the plurality of plasma processing unitsmeasured from an output-terminal-side of the matching circuits.
 2. Theinspection method for a plasma processing apparatus according to claim1, wherein the matching circuit is disconnected from the plasmaprocessing unit at the output terminal and at the input terminal, andthe AC resistance RA is measured at a first measuring pointcorresponding to the input terminal.
 3. The inspection method for aplasma processing apparatus according to claim 1, the plasma processingunit further comprising a radiofrequency supplier disposed between theradiofrequency generator and the input terminal of the matching circuit,wherein the matching circuit is disconnected from the plasma processingunit at the output terminal and at an input end of the radiofrequencysupplier, and the AC resistance RA is measured at a second measuringpoint corresponding to the input end of the radiofrequency supplier. 4.The inspection method for a plasma processing apparatus according toclaim 1, wherein the matching circuit is disconnected from the plasmaprocessing unit at the input terminal and at the output terminal of thematching circuit, and the AC resistance RB is measured at a thirdmeasuring point corresponding to the output terminal.
 5. The inspectionmethod for a plasma processing apparatus according to claim 1, theplasma processing unit further comprising a radiofrequency feederdisposed between the output terminal of the matching circuit and theelectrode, wherein the matching circuit is disconnected from the plasmaprocessing unit at the input terminal of the matching circuit and at anoutput end of the radiofrequency feeder, and the AC resistance RB ismeasured at a fourth measuring point corresponding to the output end ofthe radiofrequency feeder.
 6. The inspection method for a plasmaprocessing apparatus according to claim 1, wherein the AC resistances RAand RB are values measured at a power frequency of the radiofrequencygenerator.
 7. The inspection method for a plasma processing apparatusaccording to claim 1, wherein both the first and second predeterminedranges are less than 0.5.
 8. The inspection method for a plasmaprocessing apparatus according to claim 7, wherein both the first andsecond predetermined ranges are less than 0.4.
 9. The inspection methodfor a plasma processing apparatus according to claim 1, the matchingcircuit further comprising at least one connection point to connect thematching circuit to the ground potential portion, wherein the ACresistances RA and RB are measured for each of the connection points bysequentially switching the connection points so that only one of theconnection points is connected to the ground potential portion.
 10. Ainspection method for a plasma processing system including a pluralityof plasma processing apparatuses, each of the plasma processingapparatuses including a plurality of plasma processing units, each ofthe plasma processing units comprising: a plasma processing chamberincluding an electrode to excite a plasma; a radiofrequency generator tosupply radiofrequency power to the electrode; and a matching circuit tomatch impedances of the plasma processing chamber and the radiofrequencygenerator, the matching circuit having an input terminal connected tothe radiofrequency generator, an output terminal connected to theelectrode, and a connection point provided between the input terminaland the output terminal, the matching circuit being connected to aground potential portion via the connection point, the methodcomprising: inspecting whether a variation <RA> among the plurality ofplasma processing units defined by a first equation below is within afirst predetermined range:<RA>=(RA _(max) −RA _(min))/(RA _(max) +RA _(min)) where RA_(max) andRA_(min) are maximum and minimum values, respectively, of AC resistancesRA in the matching circuits of the plurality of plasma processing unitsmeasured from an input-terminal-side of the matching circuits; andinspecting whether a variation (RB) among the plurality of plasmaprocessing units defined by a second equation below is within a secondpredetermined range:<RB>=(RB _(max) −RB _(min))/(RB _(max) +RB _(min)) where RB_(max) andRB_(min) are maximum and minimum values, respectively, of AC resistancesRB in the matching circuits of the plurality of plasma processing unitsmeasured from an output-terminal-side of the matching circuits.
 11. Theinspection method for a plasma processing system according to claim 10,wherein the matching circuit is disconnected from the plasma processingunit at the output terminal and at the input terminal, and the ACresistance RA is measured at a first measuring point corresponding tothe input terminal.
 12. The inspection method for a plasma processingsystem according to claim 10, the plasma processing unit furthercomprising a radiofrequency supplier disposed between the radiofrequencygenerator and the input terminal of the matching circuit, wherein thematching circuit is disconnected from the plasma processing unit at theoutput terminal and at an input end of the radiofrequency supplier, andthe AC resistance RA is measured at a second measuring pointcorresponding to the input end of the radiofrequency supplier.
 13. Theinspection method for a plasma processing system according to claim 10,wherein the matching circuit is disconnected from the plasma processingunit at the input terminal and at the output terminal of the matchingcircuit, and the AC resistance RB is measured at a third measuring pointcorresponding to the output terminal.
 14. The inspection method for aplasma processing system according to claim 10, the plasma processingunit further comprising a radiofrequency feeder disposed between theoutput terminal of the matching circuit and the electrode, wherein thematching circuit is disconnected from the plasma processing unit at theinput terminal of the matching circuit and at an output end of theradiofrequency feeder, and the AC resistance RB is measured at a fourthmeasuring point corresponding to the output end of the radiofrequencyfeeder.
 15. The inspection method for a plasma processing systemaccording to claim 10, wherein the AC resistances RA and RB are valuesmeasured at a power frequency of the radiofrequency generator.
 16. Theinspection method for a plasma processing system according to claim 10,wherein both the first and second predetermined ranges are less than0.5.
 17. The inspection method for a plasma processing system accordingto claim 16, wherein both the first and second predetermined ranges areless than 0.4.
 18. The inspection method for a plasma processing systemaccording to claim 10, the matching circuit further comprising at leastone connection point to connect the matching circuit to the groundpotential portion, wherein the AC resistances RA and RB are measured foreach of the connection points by sequentially switching the connectionpoints so that only one of the connection points is connected to theground potential portion.